680 UnpDERWOOD: FERNS OF THE PHILIPPINES 
Tribe 11. Davatleae 
The eight genera represented may be distinguished as follows: 
1. Pinnae one-sided : indusium double, the inner membranous, the outer formed of the 
more or less changed leaf-margin. LINDSAEA. 
Pinnae developed on both sides of midrib, though not always equally. 2; 
2. Indusium attached only at base. 3: 
Indusium attached on three sides. 4- 
Indusium wanting; sori subterminal on the veins. MONACHOSORUM. 
3. Pinnae jointed to the rachis. NEPHROLEPIS. 
Pinnae not jointed ; leaves jointed to the rootstock, HumMata. 
Pinnae not jointed ; leaves not jointed to the rootstock. SACCOLOMA, 
4. Leaves jointed to the rootstock. 3 DAVALLIA. 
Leaves not jointed to the rootstock. 5- 
5. Leaf-lobes as long as indusium and both uniting in a special cup beneath the sorus. 
DENNSTAEDTIA. 
Leaf-lobes slightly modified, longer than the indusium. 6. 
6. Sorus with a receptacle containing tracheids; leaves scattered on a creeping root- 
stock. MICROLEPIA. 
Sorus without a tracheidal receptacle; leaves clustered. ODONTOSORIA. 
The Malaysian region is the home of certain groups of the daval- 
lioid ferns ; Humata is represented by twelve species ; Davadlia also 
by twelve species, of which six belong to the § Odontoloma, some- 
times recognized as a genus; Odontosoria by a single species, and 
Microlepia by nine; all the foregoing are included in the genus 
Davallia in Synopsis Filicum. Of the other genera Nephrolepis has 
eight nominal Philippine species, a number which may be modified, 
since the genus is sadly in need of a revision ; Lindsaea has seven- 
teen, Dennstaedtia has four, and Monachosorum and Saccoloma each 
one. 
FamMILy 7. HyMENOPHYLLACEAE 
Following the usual treatment the filmy ferns are grouped in 
two genera representing the primary divisions in the following syn 
opsis. We believe, however, that many of the genera established 
by Presl are as clearly marked natural groups as can exist among 
the ferns, and in the following treatment we have taken up such 
of Presl’s genera as occur in the Philippines, believing that others 
_ represented in tropical America and elsewhere represent equally 
natural groups. 
