Hippeastrum // is a genus of about 90 species and over 600 hybrids and cultivars of perennial herbaceous bulbous plants. They generally have large fleshy bulbs and tall broad leaves, generally evergreen, and large red or purple flowers.
Hippeastrum is a genus in the family Amaryllidaceae (subfamily Amaryllidoideae, tribe Hippeastreae, and subtribe Hippeastrineae) The name Hippeastrum, given to it by William Herbert, means "Knight's-star-lily", although precisely what Herbert meant by the name is not certain. For many years there was confusion among botanists over the generic names Amaryllis and Hippeastrum, one result of which is that the common name "amaryllis" is mainly used for cultivars of this genus, often sold as indoor flowering bulbs particularly at Christmas in the northern hemisphere. By contrast the generic name Amaryllis applies to bulbs from South Africa, usually grown outdoors. The genus is native to tropical and subtropical regions of the Americas from Argentina north to Mexico and the Caribbean.
Reproduction is generally by allogamy (cross-pollination) and Hippeastrum may be propagated by seed or offset bulbils (bulblets), although commercial ventures use in vitro techniques, or splitting of the bulb into sections. The genus has been intensely bred and cultivated since the early nineteenth century to produce large colourful showy flowers. In temperate climes these can be placed outside in the summer, and after a dormancy period, be induced to rebloom inside in the winter.
- 1 Description
- 2 Taxonomy
- 3 Distribution and habitat
- 4 Ecology
- 5 Breeding and propagation
- 6 Conservation
- 7 Cultivation
- 8 Uses
- 9 Culture
- 10 See also
- 11 References
- 12 Bibliography
- 13 Wikimedia links
Most Hippeastrum bulbs are tunicate (a protective dry outer layer and fleshy concentric inner scales or leaf bases). The bulbs are generally between 5–12 cm (2"–5") in diameter and produce two to seven long-lasting evergreen or deciduous leaves that are 30–90 cm (12"–36") long and 2.5–5 cm (1"–2") wide. The leaves are hysteranthous (develop after flowering), sessile, rarely persistent and subpetiolate.
The flowers are arranged in umbelliform inflorescences which are pauciflor or pluriflor (2-14 flowers), supported on an erect hollow scape (flower stem) which is 20–75 cm (12"–30") tall and 2.5–5 cm (1"–2") in diameter with two free bracts forming a spathe which is bivalve with free leaflets at its base. Depending on the species, there are two to fifteen large showy flowers, which are more or less zygomophic and hermaphrodite. Each flower is 13–20 cm (5"–8") across, and the native species are usually purple or red. They are funnelform (funnel shaped) and declinate (curving downwards and then upwards at the tip) in shape. The perianth has six brightly colored tepals (three outer sepals and three inner petals) that may be similar in appearance or very different. The perianth segments are subequal or unequal. The tepals are united at the base to form a short tube, usually with a rudimentary scaly paraperigonium with fimbriae or a callose ridge present at the throat.
The androecium consists of six stamens with filiform (thread like) filaments, which are fasciculate (in close bundles) and declinate or ascendent. The anthers are dorsifixed or versatile. In the gynaecium, the ovary is inferior and trilocular with pluriovulate locules. The style is filiform, and the stigma trifid. The fruit forms a trivalve capsule containing seeds which are dry, flattened, obliquely winged or irregularly discoid, hardly ever turgid, and globose (spherical) or subglobose, with a brown or black phytomelanous testa. 
Separation of Hippeastrum from Amaryllis
The taxonomy of the genus is complicated. The first issue is whether the name should more properly be Amaryllis L.. In 1753 Carl Linnaeus created the name Amaryllis belladonna, the type species of the genus Amaryllis, in his Species Plantarum along with eight other Amaryllis species. Linnaeus had earlier worked on the Estate of George Clifford near Haarlem between 1735 and 1737 describing the plants growing there in his Hortus Cliffortianus in 1738. It is to this work that he refers in his Species Plantarum. This was assumed to be the South African Cape Belladonna, although not precisely known. Clifford's herbarium is now preserved at the Natural History Museum in London.
At the time both South African and South American plants were placed in this same genus. By the early nineteenth century Amaryllis had become a polymorphic (diverse) genus with about 50 species from what we would consider a dozen genera today, and attempts were made to separate it into separate genera. This work commenced in 1819 with the contributions of the English botanist, the Revd. William Herbert in Curtis's Botanical Magazine  which he expanded in 1821 in The Botanical Register, identifying 14 species of the new genus of Hippeastrum, and only leaving three species in Amaryllis. The rest of the Amaryllis species he transferred to other genera, several of which he created. Herbert further refined his descriptions of Hippeastrum in his work on the Amaryllidaceae in 1837.
Since then a key question has been whether Linnaeus's original type was a South African plant (now Amaryllis) or a South American plant (now Hippeastrum). If the latter, the correct name for the genus Hippeastrum would then be Amaryllis and a new name would need to be found for the South African genus. In 1938 JCT Uphof claimed, with some evidence, that the plant was in fact the South American Hippeastrum equestre (Linn. fil.) Herb. (syn. Amaryllis equestris (Linn. fil.) ex Aiton, accepted name H. puniceum) a plant which Carl Linnaeus' son, Linnaeus the Younger (Linn. fil.) had described c. 1781-3 (unpublished) but soon after appearing in the Hortus Kewensis of 1789. This paper sparked a debate over the next half century, that delayed the official transfer of species from Amaryllis to Hippeastrum. This debate involved botanists on both sides of the Atlantic and the final outcome was a decision by the 14th International Botanical Congress in 1987 that Amaryllis L. should be a nomen conservandum (conserved name, i.e. correct regardless of priority) and ultimately based on a specimen of the South African Amaryllis belladonna from the Clifford Herbarium. Thus Amaryllis L. is the correct name for the South African genus, not the South American genus (Hippeastrum).
Claim for Leopoldia
The second issue is whether the name should be Leopoldia. In 1819 Herbert had proposed Leopoldia as a nomen provisorium (provisional name) for the same taxon as he called Hippeastrum in 1821. Although Leopoldia was subsequently validated (i.e. became the correct name), this was overlooked, and Hippeastrum rather than Leopoldia was used for the genus of New World amaryllids. Following Filippo Parlatore in 1845, the name Leopoldia was used for a genus of grape hyacinth species, allied to Muscari. In order to preserve the widespread usage of both Hippeastrum and Leopoldia, Fabio Garbari and Werner Greuter proposed in 1970 that Herbert's Hippeastrum and Parlatore's Leopoldia should be conserved and Herbert's Leopoldia rejected. This was accepted and Hippeastrum Herb. is now a conserved name (nomen conservandum), i.e. the correct name regardless of the fact that it does not have priority over Leopoldia.
Although the 1987 decision settled the question of the scientific name of the genus, the common name "amaryllis" continues to be used. Bulbs sold as amaryllis and described as ready to bloom for the holidays belong to the genus Hippeastrum. "Amaryllis" is also used in the name of some societies devoted to the genus Hippeastrum. Separate common names are used to describe the genus Amaryllis, e.g. "Naked Lady".
The name Hippeastrum was first given to the genus by Herbert, being derived from the Ancient Greek, meaning a "Knight's Star" from ἱππεύς (hippeus, mounted knight) and ἄστρον (astron, star), to describe the first recognized species, Hippeastrum reginae. Herbert proposed to call the genus, which he distinguished from Linnaeus' Amaryllis, Hippeastrum, or "Knight's-star-lily". He states;
"I have named [them] Hippeastrum or Knights-star-lily, pursuing the idea which gave rise to the name Equestris" (p.12).
Herbert's fourteen species included this Hippeastrum equestre. This 'equine' connection refers to Carl Linnaeus the Younger who had named (in an unpublished manuscript) a West Indian species as Amaryllis equestris, because of its similarity to the African genus Amaryllis. This name and attribution was first published by William Aiton in 1789, in his Hortus Kewensis. Which species this was is not known precisely. However, in 1795 William Curtis, described Amaryllis equestris or the Barbados lily in his Botanical Magazine, referring to Aiton:
"The spatha is composed of two leaves, which standing up at a certain period of the plant's flowering like ears, give to the whole flower a fancied resemblance of a horse's head; whether LINNÆUS derived his name of equestris from this circumstance or not, he does not condescend to inform us."
In 1803 John Sims claimed Curtis had made a mistake in this attribution, and that;
"this name was given from the remarkable likeness the front view of it has to a star of some of the orders of knight-hood; an appearance well expressed by JAQUIN's figure in the Hortus Schoenbrunnensis"
Despite much speculation, there is no definitive explanation of either Linnaeus fils or Herbert's thinking. For instance the 'Knight's Star' has been compared to Linnaeus' decoration as a Knight of the Order of the Polar Star. The Latin word equestris (of a knight, or horseman) may have been confused with equi (of a horse), or possibly Herbert was making a literary Knight's Move on the Linnaean term. The flower name has even been compared to the mediaeval weapon, the spoked mace or Morning Star which it superficially resembles.
While interspecific hybrids of Hippeastrum are relatively common, hybridization with other genera of Amaryllidaceae are more rare. The most conspicuous exception is the hybrid obtained through crossbreeding with the Mexican Sprekelia formosissima Herb. (St James's lily, Aztec lily, Jacobean lily), another member of the tribe Hippeastreae, originally called Amaryllis formosissima, which is apomictic. × Hippeastrelia is the name given to this cross. 
A number of subgenera have been proposed over the years. For instance in the 1870s and 1880s John Gilbert Baker considerably reorganised Hippeastrum. In 1878 he described nine sections of the genus, but by 1888 he included seven subgenera, namely (number of species in parentheses) Habranthus (10), Phycella (3), Rhodophiala (5), Macropododastrum (1), Omphalissa (6), Aschamia (10) and Lais (3), some of which have since been treated as separate genera (Habranthus, Rhodophiala). Baker both reduced the original number of species of Herbert, but also enlarged the genus by adding in other genera such as Habranthus, Phycella, Rhodophiala and Rhodolirion (also called Rhodolirium, and subsequently moved to Rhodophilia), which he included as separate sections of Hippeastrum. In addition, he included many new species being discovered in South America, particularly Chile. His 1878 classification included 47 species, reduced to 38 by 1888.
- Aschamia (Salisb.) Baker (e.g. H. reginae, H. andreanum, H. scopulorum, H. mandonii, H. leopoldii, H. reticulatum, H. stylosum)
- Cephaleon Traub (e.g. H. machupijchense)
- Lais (Salisb.) Baker (e.g. H. striatum, H. vittatum, H. breviflorum)
- Macropodastrum Baker (e.g. H. elegans)
- Omphalissa (Salisb.) Baker (e.g. H. aulicum, H. psittacinum, H. calyptratum, H. cybister, H. pardinum, H. miniatum, H. iguazuanum)
- Sealyana Traub (e.g.: H. reticulatum)
- Hippeastrum angustifolium Pax
- Hippeastrum arboricola (Ravenna) Meerow
- Hippeastrum aulicum (Ker Gawl.) Herb.
- Hippeastrum aviflorum (Ravenna) Dutilh
- Hippeastrum calyptratum (Ker Gawl.) Herb.
- Hippeastrum canterai Arechav.
- Hippeastrum correiense (Bury) Worsley
- Hippeastrum cybister (Herb.) Benth. ex Baker
- Hippeastrum evansiae (Traub & I.S.Nelson) H.E.Moore
- Hippeastrum ferreyrae (Traub) Gereau & Brako
- Hippeastrum iguazuanum (Ravenna) T.R.Dudley & M.Williams
- Hippeastrum leopoldii T.Moore
- Hippeastrum miniatum (Ruiz & Pav.) Herb.
- Hippeastrum papilio (Ravenna) Van Scheepen
- Hippeastrum pardinum (Hook.f.) Dombrain
- Hippeastrum petiolatum Pax
- Hippeastrum psittacinum (Ker Gawl.) Herb.
- Hippeastrum puniceum (Lam.) Voss. Syn. H. equestre (Aiton)
- Hippeastrum reginae (L.) Herb.
- Hippeastrum striatum (Lam.) H.E.Moore
- Hippeastrum reticulatum (L'Hér.) Herb. Syn H. striatifolium (Sims)
- Hippeastrum vittatum (L'Hér.) Herb.
Hybrids include Hippeastrum × 'Johnsonii'.
Distribution and habitat
Hippeastrum species are concentrated in two centres of diversity, the main one in Eastern Brazil and the other in the central southern Andes of Peru, Bolivia and Argentina, on the eastern slopes and nearby foothills. Some species are found as far north as Mexico and the West Indies. The genus is thought to have originated in Brazil where at least 34 of the species have been found. Their habitat is mainly tropical and subtropical, though those species found south of the equator, or at sufficient altitude may be considered temperate. Hippeastrum is found in a wide range of habitats. Many are found in underbrush, while others prefer full sun. Hippeastrum angustifolium is an example of a species preferring flood areas, while other species prefer a drier habitat. There are also epiphytic species such as Hippeastrum aulicum, Hippeastrum calyptratum, Hippeastrum papilio and Hippeastrum arboricola, which require air circulation around their roots, which are in the subgenus Omphalissa.
Hippeastrum hybrids and cultivars are valued for their large ornamental flowers, particularly for indoor cultivation during the northern hemisphere winter. The larger the bulb, the more flowers it will produce. The largest bulbs measure 14 to 16 inches (36 to 41 cm) in circumference and will produce three or more scapes (flower stems) with four or more blooms each. The commonest bulbs measure 10½ to 12½ inches (27 to 32 cm) with two scapes with four to six flowers each depending on the cultivar. Some bulbs put up two flower scapes at the same time; others may wait several weeks between blooms and sometimes the second scape will have only two or three flowers rather than the usual four. A bulb needs to produce large, healthy leaves in the summer growing season before it can send up a scape the following year. Bulbs are often described by the country of origin of the bulb producers, since they may have different characteristics, e.g. 'Dutch Amaryllis', 'South African Amarylllis'. Dutch bulbs usually produce flowers first, then, after they have finished blooming (hysteranthous), the plant will begin growing leaves. Bulbs from the South African growers usually put up a scape and leaves at the same time (synanthous).
Of the many hybrids, the best known are those producing flowers with red, pink, salmon, orange and white colors. Other flower colors include yellow and pale green with variations on these including multicoloring, with different colored mottling, stripes or edges on the petals. Some flowers have uniform colors or patterns on all six petals while others have more pronounced colors on the upper petals than on the lower ones.
Although many names are used to describe hybrids and cultivars, e.g. 'Large Flowering', 'Dutch', 'Royal Dutch', there are five types that are commonly sold;
- Single flower (large flowering)
- Double flower
- Miniature (dwarf, or small flowering)
- Jumbo (mammoth)
'Trumpets', as the name suggests, have flared, tube-shaped flowers. Single, double, and miniature bulbs are the ones typically sold by nurseries and other stores for the holidays in December and for Valentine's Day and Easter.
Of the commercially available Hippeastrum species, sometimes sold as 'exotic' amaryllis, Hippeastrum cybister has extremely thin petals often described as spider-like. The miniature evergreen Hippeastrum papilio or 'Butterfly Amaryllis' whose petals resemble a butterfly (papilio) has a unique color and pattern with broad rose-burgundy center stripes and striations of pale green on the upper petals and narrow stripes on the bottom three. It has been crossed with both cybister and single flower cultivars to produce hybrids with unusual striping.
Some species, such as the Uruguayan Hippeastrum petiolatum, are sterile and unable to produce seeds. H. petiolatum is a sterile triploid that reproduces asexually, producing many bulbils around the mother bulb. These are light, and easily carried on the surface of water ensuring distribution of the species during the rainy season. Other species such as Hippeastrum reticulatum are self-pollinating, reproducing by distributing seed. Although this does not guarantee genetic diversity in natural populations, it is widely used by colonising species. These two examples are not however typical of the genus, which commonly reproduces through allogamy. One mechanism that limits self-pollination is that of self-incompatibility by which seeds are only produced by pollination from other plants. Furthermore, the plant generally releases its pollen about two days before its stigma is receptive, making cross-pollination more likely. Pollinators include Humming birds in subtropical areas, and moths.
Hippeastrum species are used as food plants by the larvae of some Lepidoptera species including Spodoptera picta (Crinum grub)  as well as Pseudococcidae (Mealybugs), large, and small narcissus bulb flies (Eumerus strigatus and E funeralis), thrips, mites, aphids, snails and slugs. A fungal disease attacking Hippeastrum is Stagonospora curtisii (red blotch, red leaf spot or red fire). The leaves are also eaten by grasshoppers, and grasshoppers commonly plant egg pods in the ground near Hippeastrum bulbs, which erupt in the spring, covering the plant with nymphs.
Breeding and propagation
Hippeastrum breeding began in 1799 when Arthur Johnson, a watchmaker in Prescot, England, crossed Hippeastrum reginae with Hippeastrum vitattum, obtaining hybrids that were later given the name Hippeastrum × 'Johnsonii'  (Johnson's amaryllis, 'hardy amaryllis' or St. Joseph's lily). Johnson shared his work with the Liverpool Botanic Garden which was fortunate, since his greenhouse was destroyed in a fire. His hybrid was being cultivated in the US by the mid-nineteenth century. Many new hybrid lines followed as new species were sent to Europe from South America, the most important of which were Reginae and Leopoldii.
The Reginae strain hybrids were produced by Jan de Graaff and his two sons in the Netherlands in the mid 19th century by crossing Hippeastrum vitatum and Hippeastrum striatum with Hippeastrum psittacinum and some of the better hybrids available in Europe at the time. Some of the most successful hybrids were Graveana and Empress of India.
Leopoldii hybrids arose from the work of the British explorer and botanist Richard Pearce, an employee of James Veitch & Sons, a plant nursery. Pearce brought back specimens of Hippeastrum leopoldii and Hippeastrum pardinum from the Andes. These two species were notable for large flowers that were wide open and relatively symmetrical. Crossing these two species with the best of the Reginae strain produced a lineage of very large open flowered specimens, with up to 4-6 flowers on each scape. The Veitch nursery dominated the commercial development of Hippeastrum leopoldii and other varieties up to the early years of the twentieth century, the best of their hybrids setting the standard for modern commercial development.
The late 19th and early 20th century saw Amaryllis breeding develop in the United States, particularly in Texas, California, and Florida in conjunction with the USDA (1910–1939). The major US contribution came from the work of Henry Nehrling and Theodore Mead, whose hybrids crossed with Dutch stock have produced some modern hybrids, although not matching the European strains.
In 1946, two Dutch growers moved to South Africa and began cultivation there. Although most cultivars of Hippeastrum come from the Dutch and South African sources, bulbs are now being developed in the United States, Japan, Israel, India, Brazil and Australia. The double flowers from Japan are particularly beautiful. Nurseries may list Amaryllis bulbs as being 'Dutch', 'Israeli', 'Peruvian' etc., depending on the country of origin.
Most modern commercial hybrids are derived from the following species:
- H. vittatum
- H. leopoldii
- H. pardinum
- H. reginae
- H. puniceum
- H. aulicum
Three main methods are used for propagating Hippeastrum: seeds, bulbils and 'twin scales'. More recently micropropagation in vitro has been used on a commercial scale.
Seed multiplication may be used for the development of new cultivars or to increase the yield of native species. Seeds are generally sown in early summer in seedbeds, and then transplanted to larger containers. They require warmth frequent watering, and should not be given a dormant period. Seeds do not breed true. Plants obtained from seeds take about six years to bloom. 
Home propagation is best performed by using offset bulbils. Commercially, only cultivars that produce at least three bulbils on the mother bulb are used for this form of propagation. Plants grown from this method take three to four years to bloom.
The most common commercial propagation method is referred to as 'twin scales'. This involves the division of the bulb into 12 sections and then separating each section into twin scales connected by the basal plate. The cuttings that are derived from these are grown in moist vermiculite in the dark till bulbils appear. More recently growing them in sunlight produce a better crop.
The technique of plant tissue culture in vitro improves the propagation of Hippeastrum by decreasing the time required to reach the minimum size to start the reproductive cycle, using sections of bulbs grown in artificial media with the addition of plant hormones.
Most modern cultivars lack any fragrance although 'Dancing Queen' represents an exception. Fragrance is genetically related to flower colour (white, or pastel shades) and is a recessive characteristic, so that when fragrant and non fragrant varieties are crossed, not all progeny will be fragrant, whereas two fragrant progenitors will produce an all fragrant progeny.
- Hippeastrum arboricolum (Argentina)
- Hippeastrum aviflorum (Argentina)
- Hippeastrum canterai (Uruguay)
- Hippeastrum ferreyrae (Peru)
- Hippeastrum petiolatum (Argentina & Brazil)
Hippeastrum cultivars and species can be grown inside in pots or outside in warmer climates (Hardiness 7B-11). Many will bloom year after year provided they are given a dormant period in a cool, dark place for two months without water or fertilizer although some bulbs will start growing before the two-month period is up.
The bulb is tender and should not be exposed to frost, but is otherwise easy to grow with large rewards for small efforts, especially those that bloom inside during the winter months. Note too, that Hippeastrum can also be grown in the ground in temperate areas. Bulbs are usually sold in fall for early winter bloom. Bare-root bulbs do best planted in a pot only slightly larger than the circumference of the bulb in well-drained, organic mix (such as sterilized potting soil plus coir fiber, or equal amounts of peat moss, sand and humus), with one third of the bulb visible above the surface of the soil and two thirds buried.
After planting, sprouting requires a warm place (about 20 °C). Bulbs need light watering until the leaves and buds emerge, and need to be situated in a well-lit, cool place and watered as needed to maintain moderate soil moisture. Overwatering will cause bulb and root rot. Plants may be fed with common fertilizers that contain iron and magnesium. Blooming takes place about two months after planting. The plant's leaves should continue to grow after the flowers have faded. Summering outdoors in four or five hours of direct sunlight, plus fertilizing lightly as the season progresses, will help develop buds for the next year.
Hippeastrum bulbs can be induced to rebloom yearly by mimicking the conditions in its natural environment (cool dry winters). When foliage starts to yellow, dormancy can be induced by withholding water and placing the plant in a cool 4–13 °C (39–55 °F) dark place for six to ten weeks or until buds start to show. Even when plants are thriving outdoors in temperate climates, dormancy can be induced by withholding watering and fertilising in the northern hemisphere autumn, and bringing indoors to a cool environment prior to the first frost. Leaves will usually wither during this period and a flower stem begin to emerge after eight to ten weeks.
Bulbs can then be brought back into light, inspected for pests or rot, and repotted in fresh soil after cutting foliage to about 10 cm above the bulb. Subsequent care is as for new bulbs, as described above. Best results are obtained by transplanting every three to four years.
Cultivars and hybrids
Cultivars of Hippeastrum are popular indoor ornamental plants prized for their large brightly colored flowers (including red, pink, salmon, orange and white). As such they have a very important place in the floriculture trade for sale as cut flowers or potted plants. Although the market is dominated by the Netherlands, and South Africa. Other areas of production include Israel, Japan and the United States (Florida). Brazil also produces 17 million Hippeastrum bulbs annually.
Hippeastrum has yielded at least 64 isoquinoline alkaloids, which include anti-parasitic (e.g. candimine) and psychopharmacological activity. Due to their high alkaloid content, One alkaloid isolated from Hippeastrum vittatum (montanine) has demonstrated antidepressant, anticonvulsant and anxiolytic properties. Hippeastrum puniceum may also have therapeutic properties as it has been used in folk medicine to treat swellings and wounds.
A stylized flower of a Hippeastrum cultivar (under its common name of amaryllis) is used internationally as a symbol for organizations associated with Huntington's disease, a genetic degenerative disease of the nervous system. The widely used logo represents a double image of a head and shoulders as the flower of a growing and vibrant plant. The reduced size of the inner head and shoulders image symbolizes the diminution in a person caused by Huntington's disease. The leaves represent the protection, purpose, growth and development of the Huntington's community worldwide in its search for a cure and treatment.
- WCSP 2015.
- Herbert 1821, Hippeastrum Appendix: 31 (1821), nom. cons..
- Meerow, Alan W.; Van Scheepen, Johan; Dutilh, Julie H.A. (1997). "Transfers from Amaryllis to Hippeastrum (Amaryllidaceae)". Taxon 46 (1): 15–19. doi:10.2307/1224287.
- Tropicos, Hippeastrum Herb.
- Salisbury & Gray 1866, Gen. Pl. p. 134.
- Rafinesque 1838, Fl. Tellur. 4: 10.
- Link 1829, Handbuch 1: 193 .
- Koster 1816, Appendix Trav. Brazil: 493 .
- Salisbury & Gray 1866, Gen. Pl. p. 135.
- Rafinesque 1838, Fl. Tellur. 4: 11.
- Trans. Hort. Soc. London 4: 181 (1821), nom. rej. rejected homonym not Parl. 1845
- Rusby 1927, Mem. New York Bot. Gard. 7: 214.
- Pl. Life 7: 41 (1951).
- WCSP 2015, Synonyms .
- Norris Brenzel, Kathleen, ed. (2012). The New Sunset Western Garden Book: The Ultimate Gardening Guide. Oxmoor House. ISBN 978-0-376-03921-7. Retrieved 2013-12-20.
- Stevens, P.F. (2001). "Angiosperm Phylogeny Website: Asparagales: Amaryllidoideae". Missouri Botanical Garden. Retrieved 2013-11-26.
- "Hippeastrum". Flora of North America. Retrieved 2013-12-19.
- Dimitri, M. (1987). Enciclopedia Argentina de Agricultura y Jardinería. Tomo I. Descripción de plantas cultivadas (in Spanish). Buenos Aires: Editorial ACME S.A.C.I.
- "Funnel shaped". Kew Glossary. Retrieved 2013-12-01.
- "Declinate". Kew Glossary. Retrieved 2013-12-01.
- "Entry for Hippeastrum Herb". JSTOR Global Plants. JSTOR 013377.
- Meerow, lan W.; Fay, Michael F.; Guy, Charles L.; Li, Qin-Bao; Zaman, Faridah Q.; Chase, Mark W. (1999). "Systematics of Amaryllidaceae based on cladistic analysis of plastid sequence data". Am. J. Bot. 86 (9): 1325–1345. doi:10.2307/2656780. PMID 10487820. Retrieved 2013-12-20.
- "Fimbriae". Kew Glossary. Retrieved 2013-12-06.
- Simpson, Michael G. (2011). Plant Systematics. Academic Press. ISBN 978-0-08-051404-8. Retrieved 2013-12-01.
- "Pluriovulate". Kew Glossary. Retrieved 2013-12-01.
- de Andrade, Jean Paulo; Belén Pigni, Natalia; Torras-Claveria, Laura; Guo, Ying; Berkov, Strahil; Reyes-Chilpa, Ricardo; El Amrani, Abdelaziz; Zuanazzi, José Angelo S.; Codina, Carles; Viladomat, Francesc; Bastida, Jaume (2012). "Alkaloids from the Hippeastrum genus: chemistry and biological activity" (PDF). Rev. Latinoamer. Quím. 40 (2): 83–98. Retrieved 2013-12-01.
- Linnaeus, C. (1753). Species Plantarum. Retrieved 2013-11-29. pp. 292–293. Linnaeus' original species of Amaryllis were: A. lutea, A. atamasco, A. formossissima, A. belladonna, A. sarniensis, A. zeylanica, A. longifolia, A. orientalis and A. guttata. All of these were subsequently assigned to different genera (Sealy 1938).
- "The George Clifford Herbarium". Natural History Museum. Retrieved 2013-11-26.
- Linnaeus, C. (1737). "Amaryllis". Hortus Cliffortianus. Retrieved 2013-11-29. p. 135
- Sealy, J.R. (1939). "Amaryllis and Hippeastrum". Bulletin of Miscellaneous Information (Royal Gardens, Kew) 1939 (2): 49–68. doi:10.2307/4111685. JSTOR 10.2307/4111685. For discussion on the status of Leopoldia, see p. 65.
- Herbert, W. (1819). "Amaryllis reticulata". Curtis's Botanical Magazine 47: 2113. Retrieved 2013-11-27.
- Herbert 1821.
- Herbert, William (1837). Amaryllidaceae: Preceded by an Attempt to Arrange the Monocotyledonous Orders, and Followed by a Treatise on Cross-bred Vegetables, and Supplement. London: Ridgway. Retrieved 30 March 2014.
- Uphof, J.C.T. (1938). "The history of nomenclature - Amaryllis belladonna( Linn.) Herb., and Hippeastrum (Herb.)". Herbertia 5: 100–111. Retrieved 2013-11-29.
- Uphof, J.C.T. (1939). "Critical review of Sealy's "Amaryllis and Hippeastrum"". Herbertia 6: 163–166. Retrieved 2013-11-29.
- Garbari, F.; Greuter, W. (1970). "On the Taxonomy and Typification of Muscari Miller (Liliaceae) and Allied Genera, and on the Typification of Generic Names". Taxon 19 (3): 329–335. doi:10.2307/1219056.
- "How to Make Your Amaryllis Bloom Again". The United States National Arboretum. Retrieved 2013-11-26.
- Mathew, Brian (Spring 1999). "Hippeastrum - The secret of the knight's star". Kew Magazine (Royal Botanic Gardens, Kew). Retrieved 2013-11-26.
- Carter, Kathie (2010). "Amaryllis" (PDF). University of California Cooperative Extension. Retrieved 2013-11-30.
- "Houston Amaryllis Society". Retrieved 2013-11-26.
- Wilson, Yolanda (October 2005). "What Do You Say to a Naked Lady? (Amaryllis belladonna)". Washington State University Clark County Extension. Retrieved 2013-12-19.
- Aiton, W. "Hexandra Monogyna : Amaryllis". Hortus Kewensis 1: 417. Retrieved 2013-11-29.
- Curtis, W. (1795). "Amaryllis equestris". Botanical Magazine 9–10: 304. Retrieved 2013-11-29.
- Sims, John (1803). "Amaryllis reticulata". Curtis's Botanical Magazine. 17–18. Retrieved 2013-11-29. p. 657.
- von Jacquin, Nikolaus Joseph (1797–1804). Hortus Schoenbrunnensis. Plantarum Rariorum Horti Caesarei Schoenbrunnensis Descriptiones et Icones (4 volumes). Vienna. Retrieved 2013-11-29.
- von Jacquin, Nikolaus Joseph (1797–1804). "Amaryllis equestris (t. 63)". Hortus Schoenbrunnensis. Plantarum Rariorum Horti Caesarei Schoenbrunnensis Descriptiones et Icones. Vienna. Retrieved 2013-11-29.
- Vigneron 2008, Hippeastrum.
- Don, M. (4 January 2013). "Their huge flower trumpets are usually associated with the festive season, but plant the bulbs now and you can enjoy amaryllis in spring". Daily Mail. Retrieved 2013-11-29.
- Meerow, Alan W. (2009). "Tilting at windmills: 20 years of Hippeastrum breeding". Israel Journal of Plant Sciences 57 (4): 303–313. doi:10.1560/IJPS.57.4.303.
- Manning, R. (1974). "Sprekelia-Amaryllis cross". Plant Life 30: 85–86.
- "×Hippeastrelia". Pacific Bulb Society. Retrieved 2013-12-20.
- Baker, J.G. (1878). Trimen, Henry, ed. "An enumeration and classification of the species of Hippeastrum". Journal of Botany: British and Foreign (London: West, Newman & Company) 16: 79–85. Retrieved 1 April 2014.
- Baker, John Gilbert (1888). "Hippeastrum". Handbook of the Amaryllideæ including the Alstrœmerieæ and Agaveæ. London: Bell. p. 41. Retrieved 31 March 2014.
- "Rhodolirion Dalla Torre & Harms". Tropicos. Missouri Botanical Garden. 2014. Retrieved 1 April 2014.
- Traub, H.P. (1958). The Amaryllis Manual. New York: Macmillan. Retrieved 2013-11-30.
- Traub, H.P. (1980). "The Subgenera of the Genus Amaryllis". Plant Life 36: 43–45.
- Vargas, C.J.C. (1984). "The Peruvian Species of the Genus Amaryllis (Amaryllidaceae).". Herbertia 40: 112–134.
- Ochoa, C.M. (2006). "Hippeastrum ugentii (Amaryllidaceae: Hippeastreae), a new species from central Peru" (PDF). Phytologia 88 (2): 176–178. Retrieved 2011-11-20.
- Meerow, A.W. (1999). "Breeding Amaryllis". Herbertia 54: 67–83.
- Vigneron 2008, Amaryllidaceae épiphytes.
- Szilard, Paula. "Getting your Hippeastrum (Amaryllis) to Bloom". Tropical Plant Society. Retrieved 2013-12-02.
- "Amarilis - Hippeastrum vittatum". Infojardin. Retrieved 2013-12-02.
- "Hippeastrum". Royal Horticultural Society. Retrieved 2013-12-02.
- Fellers, J.D. (1998). "Progeny of Hippeastrum papilio". Herbertia 53: 129–144. Retrieved 2013-12-02.
- Williams, M.; Dudley, T.R. (1984). "Chromosome Count for Hippeastrum iguazuanum". Taxon 33 (2): 271–275. doi:10.2307/1221167.
- The Origin of Species: Darwin, C. (1859). The Origin of Species. London: John Murray. pp. 235, 242. Retrieved 2013-12-25.
- Vigneron 2008, Multiplication sexuée.
- Williams, M. (1980). "Self-sterility in Hippeastrum (Amaryllis) species". Amaryllis Bulletin 1: 20.
- "Pests". Hippeastrum.com. Retrieved 2013-12-20.
- Meerow, Alan (1999). "Amaryllis and Alstroemeria: Old Crops, New Potential" (PDF). Retrieved 2013-12-03.
- Hessayon, D.G. (1999). The Bulb Expert. London: Transworld Publishers.
- "Some pests you need to watch out for". Maguire's Hippeastrum Farm. Retrieved 2013-12-20.
- "Stagonospora curtisii". Pacific Bulb Society. Retrieved 2013-12-20.
- Pauline Beaumont, Pauline. "Hippeastrum.com.au". Retrieved 25 December 2013.
- Read, V. (1999). "Developments in Hippeastrum hybridization 1799–1999". Herbertia 54: 84–109.
- "Hippeastrum × johnsonii - St. Joseph's Lily". San Marcos Growers. Retrieved 2013-12-20.
- "Hippeastrum (?) x johnsoni". Bulb Society. Retrieved 2013-12-20.
- Veitch, James Herbert (2011). Hortus Veitchii: A History of the Rise and Progress of the Nurseries of Messrs James Veitch and Sons. Cambridge University Press. p. 468. ISBN 1-108-03736-4. In Veitch (2011)
- Ephrath, J.E.; Ben-Asher, J.; Baruchin, F.; Alekperov, C.; Dayan, C.; Silberbush, M. (2001). "Various Cutting Methods For the Propagation of Hippeastrum Bulbs". Biotronics 30: 75–83. Retrieved 2013-12-20.
- Stancato, G.C.; Mazzafera, P. (1995). "Effects of light on the propagation and growth of bulbs of Hippeastrum hybridum cv. Apple Blossom (Amaryllidaceae)". Sci. Agric. (Piracicaba, Braz.) 52 (2): 331–334. doi:10.1590/S0103-90161995000200021.
- Seabrook, J.; Cumming, B. (1977). "The in vitro propagation of Amaryllis (Hippeastrum spp. hybrids)". In Vitro 13 (12): 831–836. doi:10.1007/bf02615131. PMID 598852.
- Vargas, T.E.C.; Maira Oropeza, C.; de García, Eva (2006). "Propagación in vitro de Hippeastrum". Agronomía Trop. 56 (4): 621–626.
- Sultana, J.; Sultana, N.; Siddique, M.N.A.; Islam, A.K.M.A.; Hossain, M.M.; Hossain, T. (2010). "In vitro bulb production in Hippeastrum (Hippeastrum hybridum)" (PDF). Journal of Central European Agriculture 11 (4): 469–474. doi:10.5513/jcea01/11.4.867. Retrieved 2013-12-20.
- Rǎdescu., Daniela Baltac (2012). "Cercetări privind caracterele morfologice ale unor soiuri de Hippeastrum vitatum şi comportarea lor în diferite variante tehnologice" (Research on morphological characters of certain varieties of Hippeastrum vitatum and their behavior in different technological options) (PDF). BUCUREŞTI: Ph.D Thesis, Facultatea de HORTICULTURĂ (Faculty of Horticulture), UNIVERSITATEA DE ŞTIINŢE AGRONOMICE ŞI MEDICINĂ VETERINARĂ. Retrieved 2013-12-20.
- "IUCN Red List". Retrieved 2013-12-20.
- Ockenga, Starr (2002). Amaryllis. New York: Clarkson Potter. ISBN 978-0-609-60881-4. Retrieved 2013-12-20.
- "Hippeastrum 'Bestseller'". RHS Plant Selector. Royal Horticultural Society. Retrieved 2013-06-22.
- "Hippeastrum 'Belinda'". RHS Plant Selector. Royal Horticultural Society. Retrieved 2013-12-20.
- "Hippeastrum 'Star of Holland'". RHS Plant Selector. Retrieved 2013-06-22.
- Rina Kamenetsky, Hiroshi Okubo, ed. (2012). "Hippeastrum (Amaryllis)". Ornamental Geophytes: From Basic Science to Sustainable Production. CRC Press. p. 442. ISBN 1-4398-4924-2.
- de Andrade, Jean Paulo; Berkov, Strahil; Viladomat, Francesc; Codina, Carles; Zuanazzi, José Angelo S.; Bastida, Jaume (2011). "Alkaloids from Hippeastrum papilio". Molecules 16 (12): 7097–7104. doi:10.3390/molecules16087097.
- Youssef, D.T. (2001). "Alkaloids of the flowers of Hippeastrum vittatum". J. Nat. Prod. 64 (6): 839–841. doi:10.1021/np0005816. PMID 11421761.
- Flavia Schurmann Da Silva, A.; de Andrade, Jean Paulo; Bevilaqua, Lia R.M.; De Souza, Marcia Maria; Izquierdo, Ivan; Teresinha Henriques, Amélia; Silveira Zuanazzi, José Angelo (2006). "Anxiolytic-, antidepressant- and anticonvulsant-like effects of the alkaloid montanine isolated from Hippeastrum vittatum". Pharmacology, biochemistry and behavior 85 (1): 148–154. doi:10.1016/j.pbb.2006.07.027. Retrieved 2013-12-20.
- Takos & Rook 2013.
- Mitchell, S.A.; Ahmad, M.H. (2006). "A review of medicinal plant research at the University of the West Indies, Jamaica, 1948–2001". West Indian Med. J. 55 (4). doi:10.1590/S0043-31442006000400008.
- "Amaryllis Campaign". Huntington Society of Canada. Retrieved 2011-12-11.
- "Amaryllis fundraising store". Huntington's Disease Society of America. Retrieved 2011-12-11.
- "HDA homepage". Huntington's Disease Society (England & Wales). Retrieved 2011-12-11.
- "Amaryllis logo". Huntington's Disease Association Northern Ireland. Retrieved 2011-12-11.
- Hessayon, D.G. (1999). The Bulb Expert. London: Transworld Publishers Ltd.
- Rossi, Rosella (1990). Guía de Bulbos. Barcelona: Grijalbo.
- Phillips, R.; Rix, M (1989). Bulbs. London: Pan Books Ltd.
- Taylor, P. (1996). Gardening with Bulbs. London: Pavilion Books Ltd.
- Hartmann, H.; Kester, D. (1987). Propagación de plantas, principios y prácticas. México: Compañía Editorial Continental S.A. ISBN 968-26-0789-2.
- Clay, Horace F; Hubbard, James C. (1987). Tropical Exotics: Hippeastrum vittatum. University of Hawaii Press. ISBN 0-8248-1127-5.
- Rina Kamenetsky, Hiroshi Okubo, ed. (2012). "Hippeastrum (Amaryllis)". Ornamental Geophytes: From Basic Science to Sustainable Production. CRC Press. ISBN 1-4398-4924-2.
- Veitch, James Herbert (2011) . Hortus Veitchii: A History of the Rise and Progress of the Nurseries of Messrs James Veitch and Sons. Cambridge University Press. ISBN 1-108-03736-4.
- James Cullen, Sabina G. Knees, H. Suzanne Cubey, ed. (2011). The European Garden Flora Flowering Plants: A Manual for the Identification of Plants Cultivated in Europe, Both Out-of-Doors and Under Glass. Cambridge University Press. ISBN 0521761476.
- Simpson, Michael G. (2011). Plant Systematics. Academic Press. ISBN 0-08-051404-9.
- Kubitzki, K., ed. (1998). The families and genera of vascular plants. Vol.3. Berlin, Germany: Springer-Verlag. ISBN 3-540-64060-6. Retrieved 14 January 2014.
- Mabberley, David J (2013). Mabberley's Plant-Book (3 ed.). Cambridge University Press. ISBN 1107782597. Retrieved 8 January 2014.
- Singh, Gurcharan (2004). Plant Systematics: An Integrated Approach. Science Publishers. ISBN 1578083516. Retrieved 23 January 2014.
- Takos, Adam; Rook, Fred (31 May 2013). "Towards a Molecular Understanding of the Biosynthesis of Amaryllidaceae Alkaloids in Support of Their Expanding Medical Use". International Journal of Molecular Sciences 14 (6): 11713–11741. doi:10.3390/ijms140611713. Retrieved 25 December 2014.
- Koster, Henry (1816). Travels in Brazil. London: Longman, Hurst, Rees, Orme, and Brown. Retrieved 11 May 2015.
- Link, Johann Heinrich Friedrich (1829). Handbuch zur Erkennung der nutzbarsten und am häufigsten vorkommenden Gewächse. Berlin: Haude und Spener. Retrieved 5 February 2015. Digital edition by the University and State Library Düsseldorf
- Miller, Philip (1834). "Amaryllideae". Miller's dictionary of gardening, botany, and agriculture; revised. Oxford University.
- Rafinesque, C. S. (1838) . The Synoptical Flora Telluriana, With new Natural Classes, Orders and families: containing the 2000 New or revised Genera and Species of Trees, Palms, Shrubs, Vines, Plants, Lilies, Grasses, Ferns, Algas, Fungi, & c. from North and South America, Polynesia, Australia, Asia Europe and Africa, omitted or mistaken by the authors, that were observed or ascertained, described or revised, collected or figured, between 1796 and 1836 (4 vols.). Philadelphia: H. Probasco.
- Salisbury, Richard Anthony; Gray, J. E. (1866). The Genera of Plants (Unpublished fragment.). Retrieved 26 October 2014.
- Bentham, G.; J.D. Hooker (1883). "Hippeastrum". Genera plantarum ad exemplaria imprimis in herbariis kewensibus servata definita. Vol III Part II. London: L Reeve & Co. p. 713. Retrieved 24 January 2014.
- Rusby, Henry Hurd (March 1927). "Descriptions of New Genera and Species of Plants Collected on the Mulford Biologial Exploration of the Amazon Valley, 1921–1922". Memoirs of the New York Botanical Garden 7: 205–387. Retrieved 16 May 2015.
- Read, Veronica A. (2004), Hippeastrum : the gardener's amaryllis, Portland OR: Timber Press, ISBN 978-0-88192-639-2
- Worsley, Arthington (2012). The Genus Hippeastrum: A Monograph ... Nabu Press. ISBN 978-1-277-39963-9. originally published 1896
- Jamil, Khalid (2011). Hippeastrum: Technique of Bulb and Flower Production. LAP Lambert Academic Publishing. ISBN 3-8454-2259-9.
- "List of Species of the Brazilian Flora". Rio de Janeiro Botanical Garden. 2010. (Search for Hippeastrum)
- Zuloaga, F. O., O. Morrone, M. J. Belgrano, C. Marticorena & E. Marchesi. (eds.) 2008. Catálogo de las Plantas Vasculares del Cono Sur (Argentina, Sur de Brasil, Chile, Paraguay y Uruguay). Monogr. Syst. Bot. Missouri Bot. Gard. 107. 2008 ISSN: 2250-6365
- "Hippeastrum Herb.". Tropicos. Missouri Botanical Garden. 2014. Retrieved 1 April 2014.
- WCSP (2015). "World Checklist of Selected Plant Families". The Board of Trustees of the Royal Botanic Gardens, Kew. Retrieved 9 May 2015.
- RBG Kew (2013). "Kew Glossary". Royal Botanic Gardens, Kew. Archived from the original on 5 December 2013.
Articles and theses
- Herbert, William (1821). "An Appendix: Preliminary Treatise (pp. 1-14) and A Treatise &c. (pp. 15-52)". The Botanical Register (Picadilly, London: Printed for James Ridgway and Sherwood, Neely, and Sons) 7. Retrieved 2012-11-26. For references to Hippeastrum, see p. 7ff. and 31-4; for detailed descriptions of Hippeastrum splendens, see pp. 52–3.
- Dyer, R. A. (1954). "The Cape Belladonna Lily". Taxon 3 (2): 72–74. doi:10.2307/1217368. JSTOR 1217368.
- Veitch, Harry (11 March 1890). "The Hippeastrum (Amaryllis)". Journal of the Royal Horticultural Society 12: 243–260. Retrieved 25 December 2014.
- Tjaden, W. L. (November 1979). "Amaryllis belladonna and the Guernsey lily: an overlooked clue". Journal of the Society for the Bibliography of Natural History 9 (3): 251–256. doi:10.3366/jsbnh.1922.214.171.124.
- Tombolato, Antonio F.C.; Julie H.A. Dutilh; Wilson Barbosa; Renato F.A. Veiga; Thiago N. Lucon. "Brazilian descriptor for Hippeastrum hybrids" (PDF). 3rd Global Botanic Gardens Congress. Retrieved 4 April 2014.
- Vijverberg, A.J., ed. (August 1980). "De teelt van Hippeastrum (Amaryllis)" [The production of Hippeastrum (Amaryllis)]. Proefstation voor tuinbouw onder glas te naaldwijk 17. Archived from the original on 12 December 2013. Retrieved 16 May 2015.
- De Hertogh, A.A.; Gallitano, L.B. (1998). "Influence of bulb packing systems on forcing of Dutch-grown Hippeastrum (Amaryllis) as flowering potted plants in North America". HortTechnology 8 (2 (April–June)): 175–179. Retrieved 16 May 2015.
- Douglas, James (24 March 1906). "The Hippeastrum". Gardeners’ Chronicle. Retrieved 17 May 2015.
- Hibberd, Shirley (7 April 1883). Robinson, William, ed. "Lecture on the Amaryllis". The Garden: An Illustrated Weekly Journal of Gardening in All Its Branches. 23 Midsummer: 313–314. Retrieved 17 May 2015.
- Constantin, Cornelia (14 December 2007). "Hippeastrum incantator in fiecare casa (Delightful Hippeastrum in every home)" (in Romanian). Gradini.ro. Retrieved 27 March 2014.
- Reid, Duane (1997). "Amaryllis: Year-round care". Rochester Gardening. Retrieved 27 March 2014.
- Johansson, Christer (2014). "Hippeastrum". Wiki.Plantae.se (in Swedish). Retrieved 31 March 2014.
- "Hippeastrum". Gardenology. 2010. Retrieved 1 April 2014.
- Vigneron, Pascal (2008). "Amaryllidaceae". Amaryllidaceae.org (in French). Retrieved 2 April 2014.
- Vigneron, Pascal. "Hippeastrum: Bibliographie". Amaryllidaceae.org.
- Kew: RBG (2012). "Hippeastrum Care". Spring Bulbs. Royal Botanic Gardens, Kew. Archived from the original on 25 February 2012. Retrieved 16 May 2015.
- Brown, Sydney Park; Black, Robert J. (2014). "Amaryllis (Cir-1243)" (PDF). Institute of Food and Agricultural Sciences. Environmental Horticulture Department, University of Florida Extension. Retrieved 16 May 2015.
- Pertuit, A.J. (August 1995). "Understanding and Producing Amaryllis (Hort. L 63)" (PDF). Clemson University. Retrieved 16 May 2015.
- De Hertogh, A. A. (June 1998). "Home Forcing of Potted Amaryllis (Hippeastrum) (8529)". Horticulture Information Leaflet 8529. Department of Horticultural Science, North Carolina State University. Retrieved 17 May 2015.
- "Pictures of Hippeastrum species (South America)".
- PBS (2015). "Hippeastrum". Pacific Bulb Society. Retrieved 17 May 2015.
- "Emaryllis.com". Retrieved 17 May 2015. Identification of varieties
- "Amaryllis Photo Gallery". U.S. National Arboretum. March 27, 2004. Retrieved 27 March 2014.
- "Hippeastrum cultivars". International Bulb Society. under construction
- Jacob, Dan (24 March 2007). "Time Lapse Blooming of an Amaryllis" (YouTube).
|Wikimedia Commons has media related to Hippeastrum.|
|Wikispecies has information related to: Hippeastrum|