Cyathea boivinii Mett. ex Kuhn

Janssen, Thomas & Rakotondrainibe, France, 2008, A revision of the indusiate scaly tree ferns (Cyatheaceae, Cyathea subgen. Alsophila sect. Alsophila) in Madagascar, the Comoros and the Seychelles, Adansonia (3) 30 (2), pp. 221-376: 318-319

publication ID

http://doi.org/10.5281/zenodo.5190422

persistent identifier

http://treatment.plazi.org/id/03D3163A-FFE5-FFD1-3CEC-4D2F11136C30

treatment provided by

Carolina

scientific name

Cyathea boivinii Mett. ex Kuhn
status

 

33. Cyathea boivinii Mett. ex Kuhn  

REMARKS

Cyathea boivinii   is a diffi cult species widespread in Madagascar and on the Comoros and exhibits a high intraspecific variability of indusium and indument characters as well as of the degree of lamina dimorphism and pinnule dissection.Several formerly described species and varieties have been reduced to synonyms because of continuous character variation. Th e varietal key provided below is an attempt to formally recognize discrete character variation within this taxon, although the determinations of a minority of specimens may remain ambiguous. All varieties of C. boivinii   have cup-shaped, never globular, indusia and large pinnae with a usually sparse to absent abaxial lamina indument.

KEY TO THE VARIETIES OF CYATHEA BOIVINII  

1. Petiole in most specimens without scales (i.e. the scales are rapidly caducous); petiole and rachis covered with an abundant and persistent tomentum of intricate hairs and squamules; all leaves are apparently periodically and simultaneously shed; Andringitra massif ................................................................................................ 33b. var. andringitrensis  

— Petiole in most specimens with scales (i.e the scales are persistent); petiole and rachis glabrous or with a conspicuous and caducous squamulate tomentum; leaves not simultaneously shed; not restricted to the Andringitra massif .................................................... 2

2. Petiole scales reaching the first pinna pair, a noticeable sparse tomentum of crispate hairs on the abaxial face of the costulae is always present .............................. 33c. var. bevolo  

— Petiole scales restricted to the lower half of the petiole, abaxial face of the costulae glabrous or with a caducous tomentum of crispate hairs ........................................................... 3

3. Fertile and sterile pinnules slightly to strongly dimorphic, surface of the petiole base usually finely muricate ( Fig. 32N) ........................................................... 33a. var. boivinii  

— Fertile and sterile pinnules monomorphic, surface of the petiole base coarsely muricate ( Fig. 34K View FIG ) .................................................................................................................. 4

4. Mature indusia shallowly cup-shaped, at most hemispherical, with an entire rim .......... ................................................................................................... 33d. var. hildebrandtii  

— Mature indusia hemispherical to profoundly cup-shaped, dehiscing in lobes or with ir- regular slits, their rim not entire ........................................... 33e. var. parahildebrandtii