3°8 
KEYS TO THE FERNS OF BORNEO 
Subgenus II. LEPTOCIONUM. 
a. Frond up to i cm. long, subflabellate 16. H. subfiabellatum. 
ai. Frond larger, pinnately divided. 
b. Lamina plane (margin not crisped). 
c. Rachis winged throughout. 
d. Rachis and its wings about as wide 
as the segments 
d*. Rachis narrowly winged. 
e. Indusium cleft to near the base. 
/. Lips entire 
/1. Lips toothed 
£i. Indusium cleft half-way down. 
/. Marginal teeth few and small 
/i. Teeth coarse, lobe-like 
c J . Lower part of rachis naked. 
d. Lips of indusium toothed. 
e. Frond over 4 cm. long 
e*. Frond under 4 cm. long 
di. Lips entire or nearly so. 
e. Fronds 2—4 cm. long 
£i. Fronds larger. 
/. Frond very lax 
/i. Segments close together 
b 1. Margin crisped. 
c. Indusium split to the base, apex of lips 
broad, laciniate 
17. H. Hosei. 
18. H 
19. H. 
20. H. 
21. H. 
perfissum. 
Lobbii. 
edentulum. 
holochilum . 
21. H. 
22. H. 
holochilum. 
blandum. 
23. H. Baheri. 
24. 
25 - 
H. 
H. 
semijissum. 
serrulatnm. 
ci. Indusium split nearly to base, valves 
round, slightly uneven 27 
£2. Indusium split 1/3 to 2/3 of the way 
down. 
26. H.fraUvnum. 
Reinwardti . 
H. 
d. 
Back of indusium bearing teeth or 
toothed crests. 
e. Segments cut almost to costa 
ei. Segments less deeply toothed. 
/. Back of indusium bearing teeth 
28. H. sabinifnlium. 
f 1 
above middle 
Back naked above middle 
29. H. 
30. H. 
Neesii. 
denticulatum; 
d 1. Back without teeth but with ridges 
at base 31. H . brachyglossum. 
l6. H. SUBFLABELLATUM Cesati. 
Sarawak, Dutch Borneo. 
Endemic. 
