94 
habit, gemmiferous rachises, spores, sporangia and other characters. D. acuta is 
rather different from the two other species and approaches D. amplissima, but its 
cylindrical hairs and gemmiferous rachis seem to indicate its right position being here. 
I do not know any species of the Old World that is closely related to D. effusa, 
the type-species of Parapolystichum, still, it is possible that D. Wardii (Bak.) and 
D. Hornet (Bak.), both from the Seychelles, should be referred to this subgenus. 
Key. 
1. Coste and costule above with short tomentum in a furrow. 2 
— Coste and costule above glabrous; rachises rather scaly. Sori indusiate. Under- 
side with yellow, cylindrical hairs. 350. D. acuta (Mett.) C. Chr. 
2. Sori indusiate. Smaller Andine species. 351. D. exculta (Mett.) C. Chr. 
— Sori exindusiate. Often large. 352. D. effusa (Sw.) O. Ktze. 
350. Dryopteris acuta (KI.) O. Ktze. Rev. Gen. Pl. 2: 812. 1811. — Fig. 20. 
Syn. Lastrea acuta Kl. ms. — Nephrodium acutum Hook. sp. 4: 147 pt. (excl. _ 
tab. 171). 1862; Hook. and Bak. Syn 286. 
Type from Brazil, leg. SeLLow (B! Kew!). 
Rhizome creeping, 6—8 mm thick, paleaceous; scales lanceolate, entire, scarcely 
more than 1 mm broad. Stipe brownish-stramineous with several small, deciduous 
scales like rachis, which produces a bud below the apex. Lamina probably more 
than one meter high, firm, nearly coriaceous, glossy above, quadripinnatifid at base, 
tripinnatifid at the middle, in cutting agreeing with D. effusa. Basal pinne the largest, 
much produced downwards, long-stalked; middle pinne up to 35 cm long, lanceolate, 
acuminated with a serrated, sharply acute apex. Pinnule distant, lanceolate, acuminate- 
mucronate, shortly narrowed towards the base, decurrent, pinnatifid about */s of 
the way down into falcate, sharply acute, close ‘segments, the larger of which are 
obliquely toothed, the posterior basal one reduced, and broadly adnate-decurrent to 
the costa. Rachises rather scaly by small, lanceolate, brown, entire scales. Upper 
surface, incl. coste and costule quite glabrous, underside with scattered, as fresh 
bright-yellow short and thick cylindrical hairs. Veins simple, oblique. Sori a little 
supramedial. Indusia rather deciduous, reniform, with many yellow, cylindrical hairs. 
Coe acuta connects D. effusa with D. amplissima and is less divided than both. 
