Cyathea alternans
Content
Distribution
Asia-Tropical: Borneo (Sabah present, Sarawak present); Malaya (Peninsular Malaysia present); Sumatera (Sumatera present), Benkulen Distr present, Karo Plateau present, Kelanton present, Malaysia present, Negri Sembilan present, Pahang present, Penang present, Perak present, Trengganu present
Malaysia: Sumatra (Karo plateau, Benkulen Distr.), Malay Peninsula (Penang, Perak, Negri Sembilan, Pahang, Trengganu, Kelanton), Sarawak and North Borneo.
Notes
This species is usually found growing in association with C. moluccana R. Br. and always within the range of C. moluccana. The variable C. alternans has the appearance of being a series of hybrids between C. moluccana and either C. squamulata or C. ridleyi (which are bipinnate and exindusiate) with many possible combinations of characters of pinna-shape and of indusia and scales and hairs. The type specimen of C. alternans has pinnae to about 6 ½ cm wide, with 3 pairs of free adnate lobes, a few lobes longer than adjacent ones, as in the type of Alsophila janseniana v.A.v.R.; the sori have disc-shaped indusia, as shown in Hooker, Ic. Pl. t. 622, though Hooker stated later (Syn. Fil. 41) that "a depression formed by the sorus on the lobe was mistaken by the artist for an involucre". Hairs occur on the lower surface of costules in some Peninsular specimens (especially Moh. Nur 11269); I have not seen any on Bornean ones. Bullate scales appear more common in Peninsular than in Bornean specimens.
Citation
Bedd. 1892: Handb.: 2
Copel. 1947: Gen. Fil.: 99
Hook. 1844 – In: Sp. Fil.: 29
Bedd. 1883: Handb.: 10
v.A.v.R. 1908: Handb.: 17
Hose 1899 – In: J. Str. Br. R. As. Soc.: 35
Ridl. 1926 – In: J. Mal. Br. R. As. Soc.: 5
Bedd. 1867: Ferns Br. Ind.: t. 236
Domin 1930 – In: Acta Bot. Bohem.: 90
Holttum 1954 – In: Rev. Fl. Mal.: 119