1953] 



VEGETATION OF NYAS ALAND 



187 



fig trees. A deciduous strangling fig of large size {Ficus exasperata Vahl) was 

 very abundant in the forest. Several big specimens were found rotting on the 

 ground. After the death and decay of its host tree, the latticed, tubular trunk 

 of the fig seemed unable to support the weight of its own crown for any great 

 length of time. The big fig trees were a favorite haunt of monkeys and squirrels 

 which ate the fruits, only half grown on branchlets breaking into new leaf in 

 September. 



Another abundant deciduous tree of the canopy was Albizzia gwnmifera 

 (Gmel.) C. A. Sm., made conspicuous by its reddish young leaves. Associated 

 dominants collected included, most commonly, 17714, Ehretia cymosa Thonn., 

 Rauvolfia caffra Sond., and Celtis 17744. Very large trees of Khaya nyasica 

 Stapf occurred in gullies on the eastern slopes, and in the main forests giant 

 Dracaena 17614, common also on Nchisi, had stems up to 4 or 5 feet thick at 

 the base. Under subcanopy and substage tree layers, an often abundant woody 

 undergrowth contained as a characteristic small tree Rinorea burtt-davyi Dunkley, 

 bedecked with white flowers, and commonly Achyranthes bidentata Bl., Ped- 

 diea fiscberi Engl., Piper capense L. f., Coffea lignstroides S. Moore, Al- 

 lophylus buchananii Gilg, woody 17819 of the Acanthaceae, and in thinner shade 

 the extremely hard-stinging nettle 17778. Herbaceous undergrowth consisted 

 chiefly of a few common species such as Cyperus pseudoleptocladus Kiikenth., 

 17739, the ferns Pteris quadriaurita Retz and Tectaria gemmifera (Fee) Alston, 

 and under open canopy gregarious Aframomum Villi. Among numerous species of 

 Asplenium in this forest, A. auriculatum (Thunb.) Kuhn often covered dry rocks, 

 and others occurred as ground plants in moist gullies with Dryopteris prismatica 

 (Desv.) C. Chr., large Marattia salicifolia Schrad., and a balsam (Impatiens 

 walleriana Hook, f.) with showy dark carmine flowers. Also inhabiting gullies 

 was a large purple-stemmed banana (Musa 17795) in clumps up to 20 feet high. 



The primary forest was anything but rich in lianas, but fairly well pro- 

 vided with epiphytic ferns and orchids, the latter mostly in sterile condition. 

 Mosses, too, were rather prominent with, for example, Porotrichum commune 

 Hedw. enveloping lower tree trunks, Leptodontium squarrosum (Hook.) Par. 

 covering rocks, and Rhacopilum capense C. M. carpeting logs. Loxo gramme lanceo- 

 lata (Sw.) Pr., Asplenium mannii Hook., A. dregeanum Kunze, and A. sandersonii 

 Hook, grew commonly near the ground on trees, and Streptocarpus goetzei Engl, 

 on rocks. In the treetop flora a Viscum parasitized various hosts; epiphytes 

 included fleshy Peperomia reflexa (L. f.) A. Dietr., and among ferns Oleandra 

 africana R. Bonap., Asplenium aethiopicum (Burm.) Bech., and Vittaria 17672. 

 Of particular interest was Rhipsalis cassutha Gaertn., plentiful as a pendent 

 epiphyte high on canopy trees and especially the big strangling figs, and also 

 found on the rainmaker's rock. The presence of this cactus on Cholo has been 

 discussed on the background of its New and Old World distribution by Anthony 

 (1948). Whether or not a recent addition to the flora, it appeared as thoroughly 

 at home in this African mountain environment as the other epiphytes with which 

 it was associated. 



The capacity of the forest to regenerate rapidly after destructive processes 

 was demonstrated by vigorous second growth communities fringing the primary 

 forest on lands which the natives had cleared, then abandoned in their shift- 

 ing agriculture, and in openings in the forest resulting from the fall of large 

 trees. Succession began with a coarse weed-grass stage on fallow lands, and 

 passed through dense growths of herbs, shrubs, and small trees, to stands of 

 quick-growing trees as much as 60 and 70 feet tall, from which the species 

 of the primary forest finally assumed control. Many species took part in the 



