AG A FLORA OF MANILA 
a longitudinal, incomplete annulus, interrupted by the stalk, opening trans- 
versely. Indusium present or absent. 
Genera about 120, species nearly 5,000, in all parts of the world, 81 
genera and about 700 species in the Philippines. 
1. Sori densely covering the entire back of the frond, or parts of the frond. 
2. Fronds pinnate; very coarse terrestrial ferns of brackish swamps, the 
sporangia not gathered into SOPi......-........222..::::ees00- 16. Acrostichum 
2. Fronds simple, entire; epiphytic ferns from creeping rootstock the 
sporangia in contiQuous SOM1.....-2—-.-.ncssn0-o-1s--nda ceases es 14. Cyclophorus 
2. Fronds finely 3- or 4-pinnately divided, the ultimate segments small, 
the fertile ones golden-yellow on the lower surface, the indusium 
consisting of the reflexed margins of the segments...... 10. Onychium 
1. Sori definite, on the back of the frond, scattered, or in al rows, 
not strictly marginal. 
2. Fronds entire, dimorphous, the sori reticulate, following the nerves 
over the’ entire lower surtare. 20008 4 ARE 6. Hemionitis 
2. Fronds pinnately lobed, pinnate, or decompound. 
3. Sori round or nearly so. 
4. Indusium present. 
5. Pinnae articulated to the rachis.....................0.22..... 2. Nephrolepis 
5. Pinnae not articulated to the rachis........................ 1. Dryopteris 
4, Indusium none. 
6. Fronds? all: salilee: (13.0) 81 tase oh Jae aD 13. Polypodium 
5. Fronds dimorphous; basal, sterile, concave, humus-gathering ones 
which are at first green, soon becoming brown, and ordinary 
green, pinnately lobed fertile fronds.................... 15. Drynaria 
3. Sori elongated. 
4. Indusium wanting; finely pinnately compound ferns, the lower 
surface covered with white waxy powder................ 7. Ceropteris 
4. Indusium present. 
5. Veins forming regular areolae, or if not then the sori often 
double, on both sides of the veinlets........................ 4. Athyrium 
5. Veins not forming regular areolae, except sometimes at the 
margin, the sori always simple...........................-.. 5. Asplenium 
1. Sori marginal, definite. 
2. Indusium half cup-shaped, attached by the base and margins, opening 
Gritward: 7. UA. LL Se, SY 1 ee 3. Davallia 
2. Indusium formed of the refiexed modified or unmodified margin of the 
frond. 
3. Sori borne on the inner face of the reflexed lent! -margin. 
11. Adiantum 
3. Sori not on the inner surface of the refiexed-margin, protected by 
it, but borne on the frond itself. 
4. Sori linear, on a strand connecting the tips of the veins, the 
reflexed margin of the leaf continuous; usually coarse, not 
“nely. ‘divided Terris. o00) 02 ece, oe eh ee 12. Pteris 
4, Sori terminal on the veins, at first distinct, later confluent, the 
reflexed margin of the leaf interrupted; slender, finely divided 
Farr LOI wh hh ilo GN: aeRO DY Oe yh DE es 9. Cheilanthes 
2. Indusium none; otherwise very similar to Cheilanthes.... 8. Notholaena 
