Alsophila borbonica
| Alsophila borbonica | |
|---|---|
| |
Scientific classification 
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| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Division: | Polypodiophyta |
| Class: | Polypodiopsida |
| Order: | Cyatheales |
| Family: | Cyatheaceae |
| Genus: | Alsophila |
| Species: | A. borbonica
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| Binomial name | |
| Alsophila borbonica | |
| Synonyms[1] | |
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Alsophila borbonica, synonym Cyathea borbonica,[1] is a tree fern endemic to Mauritius and Réunion. There are several natural forms and varieties.
Description[edit]
It reaches a height of roughly 2 meters, with a dark, hairy, scaly trunk. Its spreading leaves are dark green fronds. Each frond has a relatively small stem (stipe). Each leaf also divides only twice (bipinnate):
- The central midrib of the frond (rachis) branches into many horizontal leaflets (pinnae).
- Each pinna midrib bears many small leaflets (pinnules).
Forms and distribution[edit]
There are two natural Mauritian varieties, which occur mainly in the upland forest in the higher parts of the island, and are both endangered. There is one natural Reunionese variety:
- A. borbonica var. borbonica (Réunion)
- A. borbonica var. latifolia (Mauritius), which bears an umbrella-shaped crown
- A. borbonica var. sevathiana (Mauritius), which bears a funnel-shaped crown
Related species[edit]
In Mauritius, they share the island with several other tree ferns - the naturally occurring Mauritian species Alsophila grangaudiana and Alsophila celsa - and the alien non-indigenous Sphaeropteris cooperi which is introduced from its native Australia.
In Réunion, they share the island with the naturally occurring Réunionese species Alsophila glaucifolia and Alsophila celsa - and also with the introduced Sphaeropteris cooperi.[2]
Alsophila borbonica can be distinguished from all of these other species by its small stipe and by its fronds' two-level division.[3]
-
The alien Sphaeropteris cooperi can be distinguished by the red and white hairs on its new fronds. -
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References[edit]
- ^ a b c "Alsophila borbonica (Desv.) R.M.Tryon". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 2021-07-25.
- ^ A revision of the fern family Cyatheaceae in the Mascarene Islands (2006)
- ^ M. Glaubrecht (2010): Evolution in Action: Case studies in Adaptive Radiation, Speciation and the Origin of Biodiversity. Springer Science & Business Media. Science. p.13.