90 
THE FERNS OF SOUTH AFRICA 
or not constant, consequently these two genera could be found 
on the same frond. General habit has therefore been relied 
upon more in bringing together under Dryopteris some species 
with and others without indusium, as well as some with 
reniform sori and others with sori elongated. The genus 
is consequently less artificial but more difficult than formerly. 
From Aspidium it is distinguished by the venation, from 
Leptochilus by the latter having dimorphous fronds, and 
from Polystichum by the indusium when present being reni- 
form, riot peltate. The species are widely distributed, and 
among the most common ferns in South Africa. 
Synopsis of the species : 
§ Fronds pinnate or 2-pinnatifid, sori round. 
1 6. D. orie?ttalis. Rhizome long, slender; sori mostly one to each 
pinnule ; veins free, simple. 
17. D. Bergiana. Rhizome short, with sub-erect crown ; sori 
numerous in the pinnules ; veins free, simple ; texture thin ; 
lower pinnae reduced. 
18. D. patens. Similar to D. Bergiana , except lower pinnae not 
reduced. 
19. D. mauritiana. Pinnules not close ; texture thin ; veins 
simple ; two or more pairs of veinlets from neighbouring pinnae 
meeting. Indusium present. 
20. D. mollis , Pinnules close or overlapping ; texture firmly 
herbaceous ; stipe, rachis and pinnules villose ; veins simple, 
several lower pairs from neighbouring pinnae meeting. Indusium 
usually present. 
21. D. gongy lodes. Frond pinnate, pinnae lobed ; texture coria- 
ceous, nearly glabrous, several pairs of veinlets from neighbouring 
lobes meeting. Sori near the junction of the veins. Indusium 
small, fugacious. 
22. D.prolifera. Frond pinnate, pinnae lobed ; veins from neigh- 
bouring lobes meeting ; sori on the middle of the veinlet, often 
irregular. Indusium not present. 
23. D. silvatica. Frond pinnate, pinnae lobed ; veins from neigh- 
bouring lobes meeting ; sori small, close to the mid-rib of the 
lobe ; indusium not present. 
24. D. thelypteris. Veins free, forked. Rhizome long, slender. 
§§ Frond 2-pinnatifid, sori oblong or elongated. 
25. D. africana. Indusium absent. 
