Cyathea humilis

Cyathea humilis
Scientific classification
Kingdom:	Plantae
Division:	Pteridophyta
Class:	Pteridopsida
Order:	Cyatheales
Family:	Cyatheaceae
Genus:	Cyathea
Subgenus:	Cyathea
Section:	Alsophila
Species:	C. humilis
Binomial name
Cyathea humilis Hieronymus in Engler & Prantl, 1895
Varieties
C. h. var. humilis Hieronymus in Engler & Prantl, 1895 C. h. var. pycnophylla Holttum, 1981
Synonyms
Alsophila holstii Hieronymus in Engler & Prantl, 1895 (non Cyathea holstii Hieronymus, 1895; quae Cyathea mossambicensis) ?Cyathea usambarensis Hieronymus in Engler & Prantl, 1895 Cyathea stuhlmannii Hieronymus in Engler & Prantl, 1899 Alsophila stuhlmannii (Hieronymus in Engler & Prantl) Tryon, 1970 Cyathea ulugurensis Hieronymus in Engler & Prantl, 1899 Cyathea uluguruensis (Hieronymus in Engler & Prantl) J. E. Braggins & M. F. Large orth. var., 2004 Cyathea opizii Domin, 1929 Cyathea usambarensis Domin, 1929

Cyathea humilis is a species of tree fern native to Kenya, as well as the Usambara and Uluguru Mountains in Tanzania, where it grows in wet forest at an altitude of 1100-2000 m. The trunk of this plant is erect and 2-3 m tall. Fronds are pinnate and 1-2 m in length. Dead fronds are often retained in the typical variety (C. h. var. humilis), forming an irregular skirt around the trunk. The rachis and stipe are light brown in colouration. Scales are present towards the base of the stipe. They are dark, glossy, and have narrow, fragile edges. Sori occur at the forks of veins and are protected by thin, reduced indusia.

Two distinct varieties of C. humilis are known. C. h. var. pycnophylla, the lesser known form, is endemic to the Mogodoro district of Tanzania. This variety differs in the shape of its fronds and does not retain them as a skirt around its trunk. Further study is needed to more precisely determine the taxonomic status of these plants.

Large and Braggins (2004) note that the holotype of C. humilis is "almost certainly a juvenile of Cyathea stuhlmannii", a taxon also described by Hieronymus. Since the specific epithet humilis is older, it takes precedence, and C. stuhlmannii should be regarded as a junior synonym.

References

• Large, Mark F. & Braggins, John E. 2004. Tree Ferns. Timber Press, Inc., p. 144. ISBN 0-88192-630-2
• The International Plant Names Index: Cyathea humilis