Ornithogalum

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Ornithogalum
Ornithogalum umbellatum close-up2.jpg
Ornithogalum umbellatum
Scientific classification e
Kingdom: Plantae
Clade: Angiosperms
Clade: Monocots
Order: Asparagales
Family: Asparagaceae
Subfamily: Scilloideae
Tribe: Ornithogaleae
Genus: Ornithogalum
L.[1]
Type species
Ornithogalum umbellatum
Species

See text.

Synonyms[2]
Linnaeus' description of Ornithogalum 1753

Ornithogalum is a genus of perennial plants mostly native to southern Europe and southern Africa[3] belonging to the family Asparagaceae. There are some species native to other areas such as the Caucasus.[4] Growing from a bulb, species have linear basal leaves and a slender stalk, up to 30 cm or more tall, bearing clusters of typically white star-shaped flowers, often striped with green.[citation needed] The common name of the genus, Star-of-Bethlehem, is based on its star-shaped flowers, after the Star of Bethlehem that appeared in the Biblical account of the birth of Jesus. The number of species has varied considerably, depending on authority, anywhere from 50 to 300.

Description[edit]

Ornithogalum are perennial bulbous geophytes with basal leaves. Sensu lato the genus has the characteristics of the Ornithogaleae tribe as a whole, since the tribe is monotypic in that sense. Sensu stricto the genus is characterised by long linear to oblong-lanceolate (lance shaped) leaves, sometimes with a white longitudinal band on the adaxial (upper) side, an inflorescence that is corymbose or pseudocorymbose, tepals that are white with a longitudinal green band only visible on the abaxial (lower) side, a capsule that is obovate or oblong, and truncate with six noticeable ribs in section and seeds that are globose with a prominently reticulate (net like pattern) testa.[5] The bulbs are ovoid with free or concrescent scales.[6]

The longitudinal band on the leaves is thought to be caused by an interruption of palisade tissue in the central portion of the leaf. This is an apomorphy that was not present in the early lineage of this clade, but is also seen in some Albuca species.[5]

Taxonomy[edit]

Ornithogalum was originally described by Linnaeus in 1753, with twelve species, which he placed in the Hexandria Monogynia (six stamens, one carpel).[1] When Adanson formed the Liliaceae family in 1763 he placed Ornithogalum there, where it largely remained till this very large family was dismembered towards the end of the twentieth century. Specifically he included the genus with the 'onions' (now Allioideae).

By the 1870s, as Baker describes in his revision of the family,[7] the taxonomy of Liliaceae had become vast and complicated. Baker placed Ornithogalum in the tribe Scilleae,[8] one of eight tribes that he divided the Liliaceae into. He then further subdivided the genus into seven subgenera. Of those, the first, Heliocharmos, corresponds to the modern Ornithogalum sensu stricto, with 23 species.[9]

Later, in the United Kingdom Bentham and Hooker published their volume on the Liliaceae in Latin in 1883.[10] They divided the family into 20 tribes and placed Ornithogalum in the Scilleae tribe with 19 other genera, and indicated that there were 70 species.[11] In the German literature the taxonomic system of Engler completed its classification of Liliaceae in 1888.[12] He divided the family into twelve subfamilies and subordinate tribes. Ornithogalum was then placed in the Lilioideae subfamily and Scilleae tribe together with 21 other genera. The 70 species of Ornithogalum were then further divided up into six sections,[13] with section Heliocharmos corresponding to Baker's subgenus.

Ornithogalum is one of four genera in the tribe Ornithogaleae, the largest tribe within the Scilloideae subfamily of Asparagaceae.[14] Historically it was treated as part of the Ornithogaloideae subfamily of Hyacinthaceae, now obsolete terms. The preferred treatment being to consider the Hyacinthaceae as subfamily Scilloideae of Asparagaceae. The original subfamilies within Hyacinthaceae becoming tribes of subfamily Scilloideae. Thus subfamily Ornithogaloideae became tribe Ornithogaleae.[14][5]

The precise taxonomy of the Ornithogaloideae/Ornithogaleae has been problematic since at least the time of Linnaeus.[15] The Ornithogaloideae were one of four major clades within Hyacinthaceae.[16] Phylogenetic analysis subsumed all of that subfamily into the genus Ornithogalum with about 300 species. This sensu lato reduction of Speta's fourteen genera[17] into one was not widely accepted, even though they were polyphyletic, and had a number of problems. (This also had the effect of eliminating Galtonia as a genus, under which a number of Ornithogalum species are still sold.)[5]

Further analysis with wider sampling (70 compared to 40 taxa) and a third plastid region (matK) revealed the presence of three clades (A, B and C) within Ornithogaleae/Ornithogalum. Consequently a new classification was proposed with three tribes and four genera, Ornithogalum corresponding to Clade C, placed in tribe Ornithogaleae, but further subdivided into subgenera and sections, with 160 species.[18][5] Galtonia was retained as a taxa but at the subgenus level. An alternative approach was suggested combining plastid gene sequences with nuclear DNA sequences, morphology and biogeography.[5] This supported Manning's Clade C within which Ornithogalum was contained, but the very large subgenus Ornithogalum was noted to still be heterogeneous, which they had managed by treating it as seven sections. This study suggested reversing the sensu lato (lumping) approach of Manning et al., reverting to separate genera (splitting), thus resurrecting Galtonia.

The sensu stricto classification of Martinez-Azorin et al. reduces the number of species to 50 as originally proposed by Speta.[17] Thus any consideration of the genus needs to be examined as to whether it refers to sensu stricto, the 50 species considered by Speta (1988) and Martinez-Azorin et al. (2011), or sensu lato, the much larger genus envisaged by Manning et al. (2009).

Subdivision[edit]

This very large genus has long been divided into many subgenera. The Flora Europaea (1980) lists fifteen subgenera, many of which had at various times been separate distinct genera.[6] Having originally subsumed all of the Ornithogaleae genera into the single genus Ornithogalum,[16] Manning et al. later subdivided this now very large genus into four subgenera after resurrecting three of the original subsumed genera (Albuca, Pseudogaltonia, Dipcadi).[18] As proposed by them the genus has the following structure:

  • subgenus Avonsera (Speta) J.C. Manning & Goldblatt (monotypic: Ornithogalum convallarioides)
  • subgenus Galtonia (Decne.) J.C. Manning & Goldblatt (7 species)
  • subgenus Aspasia (Salisb.) Oberm.[19] (30 species)
  • subgenus Ornithogalum (7 sections, 120 species)

Species[edit]

There are about 180 species, of which the best known are O. umbellatum, O. saundersiae, O. arabicum and O. thyrsoides.[20]

Species formerly placed in Galtonia include: [21]

Etymology[edit]

Ornithogalum, or Ornitogalon in old French, is derived from two Greek words, ορνισ ornithos (bird) and gala (milk), thought to be related to the white colour of the flowers.[19]

Distribution and habitat[edit]

Species are widely distributed over several continents including Africa (excluding the Tropic of Cancer) including Madagascar, Asia (as far as Afghanistan) and Europe.[6][3] The genus sensu stricto encompasses the species from Eurasia and North Africa.

Uses[edit]

Vase of cut Ornithogalum thyrsoides flower stems

Ornithogalum species may be sold as cut flowers, particularly O. arabicum, O. dubium, O. saundersiae and O.thyrsoides.[22] They are also sold as ornamental garden flowers.

Toxicity and use in alternative medicine[edit]

Some of the plants in the genus are poisonous, and have been known to kill grazing animals. Others are edible and used as vegetables. The bulbs contain alkaloids[23] and cardenolides,[3] which are toxic.

Ornithogalum has been listed as one of the 38 plants used to prepare Bach flower remedies,[24] a kind of alternative medicine promoted for its effect on health. However according to Cancer Research UK, "there is no scientific evidence to prove that flower remedies can control, cure or prevent any type of disease, including cancer".[25]

Gallery[edit]

See also[edit]

References[edit]

Bibliography[edit]

Flora[edit]

Historical sources[edit]

Databases[edit]