|A Hippeastrum cultivar in flower|
Hippeastrum // is a genus of about 90 species and 600+ hybrids and cultivars of bulbous plants in the family Amaryllidaceae, subfamily Amaryllidoideae, native to tropical and subtropical regions of the Americas from Argentina north to Mexico and the Caribbean. Some species are grown for their large showy flowers. For many years there was confusion amongst 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, which are widely used as indoor flowering bulbs. The generic name Amaryllis applies to bulbs from South Africa, usually grown outdoors.
|This section does not cite any references or sources. (October 2011)|
Most Hippeastrum bulbs are 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 flower stem is erect, 30–75 cm (12"–30") tall, 2.5–5 cm (1"–2") in diameter and is hollow. Depending on the species, it bears two to fifteen large flowers, each of which is 13–20 cm (5"–8") across with six brightly colored tepals (three outer sepals and three inner petals) that may be similar in appearance or very different. Some species are epiphytic (H. calyptratum, H. aulicum, H. papilio and H. arboricola) and need good air circulation around their roots. Seedlings will flower in 3 to 5 years. Hippeastrum species are used as food plants by the larvae of some Lepidoptera species including Hypercompe indecisa.
The taxonomy of the genus is complicated. The first issue is whether the name should be Amaryllis. In 1753 Carl Linnaeus created the name Amaryllis belladonna, the type species of the genus Amaryllis. At the time both South African and South American plants were placed in the same genus; subsequently they were separated into two different genera. The key question is whether Linnaeus's type was a South African plant or a South American plant. If the latter, the correct name for the genus Hippeastrum would be Amaryllis. Alan W. Meerow et al. have briefly summarized the debate, which took place from 1938 onwards and involved botanists on both sides of the Atlantic. The outcome was a decision by the 14th International Botanical Congress in 1987 that Amaryllis L. should be a conserved name (i.e. correct regardless of priority) and ultimately based on a specimen of the South African Amaryllis belladonna from the Clifford Herbarium at the British Museum. Thus Amaryllis L. is not the correct name for the South American genus.
The second issue is whether the name should be Leopoldia. In 1821, William Herbert published the genus name Hippeastrum. Earlier, in 1819, he had proposed Leopoldia as a provisional name (nomen provisorium) for the same taxon. 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 differently. Bulbs sold as amaryllis and described as "ready to bloom for the holidays" belong to this genus (Hippeastrum). "Amaryllis" is also used in the name of societies devoted to the genus Hippeastrum. Different common names are used for the genus Amaryllis, e.g. "naked lady".
Cultivars of Hippeastrum are popular bulbous flowers for indoor growing. 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. The very large, decorative flowers can also be grown outside in temperate areas. Bulbs are generally offered in the fall for early winter bloom. Bare-root new bulbs should be planted in a well-drained, organic mix (sterilized potting soil plus coir fiber), with one third of the bulb visible above the surface of the soil. Bulbs require light watering until leaves and buds emerge, then should be situated in a well-lit and cool place and watered as needed to maintain moderate soil moisture, as overwatering will cause bulb and root rot. When flowers have faded, one should allow foliage to mature; summering outdoors in bright shade and fertilizing lightly as the season progresses will help develop buds for the following fall. When foliage starts to yellow, one should start withholding water, and bulbs should be placed in cool dark place for six weeks or until buds start to show. Bulbs should be brought back into light, inspected for pests or rot, and repotted in fresh soil. Subsequent care is as for new bulbs, as described above. 
|This section does not cite any references or sources. (December 2011)|
The first commercial breeders of Hippeastrum were Dutch growers who imported several species (see list) from Mexico and South America and began developing cultivars and hybrids from them in the 18th century; the first of these reached North America early in the 19th century. In 1946 two Dutch growers moved to the Union of 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.
||This section needs additional citations for verification. (December 2011)|
In general only a large bulb will put up more than one flower scape or spike but this depends on the cultivar itself; some smaller bulbs have two while some larger bulbs make only one. A bulb must produce at least four large, healthy leaves in the summer growing season before it can send up a scape the following year. 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. Dutch bulbs usually produce flowers first, then, after it has finished blooming, the plant will begin growing leaves. Bulbs from the South African growers usually put up a scape and leaves at the same time.
The flower colors include red, rose, pink, white, orange, yellow, and pale green with variations on these including different colored stripes and 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.
There are five types: 1) single flower; 2) double flower; 3) miniature; 4) cybister; and 5) trumpet. Cybisters have extremely thin petals and are often described as spider-like. 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.
The miniature H. papilio (which is a true species, i.e., not a cultivar or hybrid but the actual plant that grows in the wild) 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.
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.
- Hippeastrum aglaiae (A.Cast.) Hunz. & A.A.Cocucci
- Hippeastrum amaru (Vargas) Meerow
- Hippeastrum andreanum Baker
- Hippeastrum angustifolium Pax
- Hippeastrum anzaldoi (Cárdenas) Van Scheepen
- Hippeastrum apertispathum (Traub) H.E.Moore
- Hippeastrum arboricola (Ravenna) Meerow
- Hippeastrum argentinum (Pax) Hunz.
- Hippeastrum aulicum (Ker Gawl.) Herb.
- Hippeastrum aviflorum (Ravenna) Dutilh
- Hippeastrum blossfeldiae (Traub & J.L.Doran) Van Scheepen
- Hippeastrum brasilianum (Traub & J.L.Doran) Dutilh
- Hippeastrum breviflorum Herb.
- Hippeastrum bukasovii (Vargas) Gereau & Brako
- Hippeastrum caiaponicum (Ravenna) Dutilh
- Hippeastrum calyptratum (Ker Gawl.) Herb.
- Hippeastrum canterai Arechav.
- Hippeastrum caupolicanense (Cárdenas) Van Scheepen
- Hippeastrum chionedyanthum (Cárdenas) Van Scheepen
- Hippeastrum condemaitae (Vargas & E.Pérez) Meerow
- Hippeastrum correiense (Bury) Worsley
- Hippeastrum crociflorum Rusby
- Hippeastrum curitibanum (Ravenna) Dutilh
- Hippeastrum cuzcoense (Vargas) Gereau & Brako
- Hippeastrum cybister (Herb.) Benth. ex Baker
- Hippeastrum damazianum Beauverd
- Hippeastrum divijulianum (Cárdenas) Meerow
- Hippeastrum doraniae (Traub) Meerow
- Hippeastrum elegans (Spreng.) H.E.Moore
- Hippeastrum escobaruriae (Cárdenas) Van Scheepen
- Hippeastrum espiritense (Traub) H.E.Moore
- Hippeastrum evansiae (Traub & I.S.Nelson) H.E.Moore
- Hippeastrum ferreyrae (Traub) Gereau & Brako
- Hippeastrum forgetii Worsley
- Hippeastrum fragrantissimum (Cárdenas) Meerow
- Hippeastrum fuscum Kraenzl.
- Hippeastrum gertianum (Ravenna) Dutilh
- Hippeastrum glaucescens (Mart. ex Schult. & Schult.f.) Herb.
- Hippeastrum goianum (Ravenna) Meerow
- Hippeastrum guarapuavicum (Ravenna) Van Scheepen
- Hippeastrum harrisonii (Lindl.) Hook.f.
- Hippeastrum hemographes (Ravenna) Dutilh
- Hippeastrum hugoi (Vargas) Gereau & Brako
- Hippeastrum iguazuanum (Ravenna) T.R.Dudley & M.Williams
- Hippeastrum incachacanum (Cárdenas) Van Scheepen
- Hippeastrum intiflorum (Vargas) Gereau & Brako
- Hippeastrum kromeri (Worsley) Meerow
- Hippeastrum lapacense (Cárdenas) Van Scheepen
- Hippeastrum leonardii (Vargas) Gereau & Brako
- Hippeastrum leopoldii T.Moore
- Hippeastrum leucobasis (Ravenna) Dutilh
- Hippeastrum macbridei (Vargas) Gereau & Brako
- Hippeastrum machupijchense (Vargas) D.R.Hunt
- Hippeastrum mandonii Baker
- Hippeastrum maracasum (Traub) H.E.Moore
- Hippeastrum marumbiense (Ravenna) Van Scheepen
- Hippeastrum miniatum (Ruiz & Pav.) Herb.
- Hippeastrum mollevillquense (Cárdenas) Van Scheepen
- Hippeastrum monanthum (Ravenna) Meerow
- Hippeastrum morelianum Lem.
- Hippeastrum nelsonii (Cárdenas) Van Scheepen
- Hippeastrum oconequense (Traub) H.E.Moore
- Hippeastrum papilio (Ravenna) Van Scheepen
- Hippeastrum paquichanum (Cárdenas) Dutilh
- Hippeastrum paradisiacum (Ravenna) Meerow
- Hippeastrum paranaense (Traub) Meerow
- Hippeastrum pardinum (Hook.f.) Dombrain
- Hippeastrum parodii Hunz. & A.A.Cocucci
- Hippeastrum petiolatum Pax
- Hippeastrum pilcomaicum (Ravenna) Meerow
- Hippeastrum psittacinum (Ker Gawl.) Herb.
- Hippeastrum puniceum (Lam.) Voss
- Hippeastrum reginae (L.) Herb.
- Hippeastrum reticulatum (L'Hér.) Herb.
- Hippeastrum rubropictum (Ravenna) Meerow
- Hippeastrum santacatarina (Traub) Dutilh
- Hippeastrum scopulorum Baker
- Hippeastrum starkiorum (I.S.Nelson & Traub) Van Scheepen
- Hippeastrum striatum (Lam.) H.E.Moore
- Hippeastrum stylosum Herb.
- Hippeastrum teyucuarense (Ravenna) Van Scheepen
- Hippeastrum traubii (Moldenke) H.E.Moore
- Hippeastrum umabisanum (Cárdenas) Meerow
- Hippeastrum vanleestenii (Traub) H.E.Moore
- Hippeastrum variegatum (Vargas) Gereau & Brako
- Hippeastrum viridiflorum Rusby
- Hippeastrum vittatum (L'Hér.) Herb.
- Hippeastrum wilsoniae L.J.Doran & F.W.Mey.
- Hippeastrum yungacense (Cárdenas & I.S.Nelson) Meerow
- Sunset Western Garden Book, 1995:606–607
- Stevens, P.F. (2001 onwards), Angiosperm Phylogeny Website: Asparagales: Amaryllidoideae
- 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
- 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
- Herbert, W. (1821), An appendix: [General index to the Botanical magazine, vol. 43-48 containing a treatise on bulbous roots], London: Printed for James Ridgway and Sherwood, Neely, and Sons, p. 7
- E.g. How to Make Your Amaryllis Bloom Again, The United States National Arboretum, retrieved 2011-11-28
- E.g. Houston Amaryllis Society, retrieved 2011-11-28
- Ockenga, Starr (2002). Amaryllis. Clarkson Potter. ISBN 978-0-609-60881-4.
- Fellers, J.D. (1998), "Progeny of Hippeastrum papilio", Herbertia 53: 129–144, retrieved 2011-12-12
- 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
- WCSP (2011), World Checklist of Selected Plant Families, The Board of Trustees of the Royal Botanic Gardens, Kew, retrieved 2011-11-20, search for "Hippeastrum"
- Ochoa, C.M. (2006), "Hippeastrum ugentii (Amaryllidaceae: Hippeastreae), a new species from central Peru", Phytologia 88 (2): 176–178, retrieved 2011-11-20
- Ockenga, Starr (2002), Amaryllis, New York: Clarkson Potter, ISBN 978-0-609-60881-4
- Read, Veronica A. (2004), Hippeastrum : the gardener's amaryllis, Portland OR: Timber Press, ISBN 978-0-88192-639-2
- Amaryllis/Hippeastrum identification
- Romanian article about Hippeastrum
- Forum for Hippeastrum and Amaryllis
- Hippeastrum Care - Royal Botanic Gardens
- RHS advice for the UK
- Pacific Bulb Society: Hippeastrum
- University of Florida Amaryllis information
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