UNDERWOOD: FERNS OF THE PHILIPPINES 681 
The Philippine genera are as follows: 
I. Indusium tubular; receptacle filiform exserted. ( Zrichomanes Syn. Fil.) 2; 
Indusium 2-valved, formed of two divided laminae of the leaf ; receptacle shorter 
than the indusium or barely protruding. ( flymenophyllum Syn. Fil. ) 6. 
2. Margin of the indusium entire, 3- 
Margin of the indusium 2-lipped. 5. 
3. Receptacle terminating in a rounded head. CEPHALOMANES.* 
Receptacle uniformly terete. 4. 
4. Leaves and indusia bordered by rows of minute cells. ABRODICTYUM.+ 
Leaves of uniform texture not bordered. TRICHOMANES, 
5. Indusium contracted below the lips, bordered by the tissue of the leaf. 
DIDYMOGLOossUM. t 
Tndusium lateral, subpedicellate, not contracted nor bordered. MERINGIUM. 3 
6. Receptacle clavate ; leaves smooth ; sporangia sessile. HYMENOPHYLLUM. 
Receptacle globose-thickened at the summit ; leaves often covered or margined with 
simple or stellate hairs, sometimes smooth ; sporangia stipitate. 
SPHAEROCIONIUM. || 
Of the above genera Cephalomanes, Abrodictyum, and Meringium 
are each represented by a single species, Sphaerocionium and 
Didymoglossum by six each ; Hymenophyllum still has a residue of 
fourteen species, and Zrichomanes a still larger one of twenty-four. 
There has been no modern monograph of this family, so that these 
numbers are likely to be varied greatly aside from future additions 
to the flora. 
IV. SALVINIALES 
Both families of this order are represented in the Philippines: 
the floating Salviniaceae by a single species of Azo//a, and the 
rooting Marsileaceae by a single species of Marsi/ea with the usual 
* Cephalomanes Presl, Hymenophyllaceae, 17. f/. 5. 1843. Monotypic ; based 
on C. atrovirens Presl (Luzon, Cuming, no. 16g); there ‘was evidently a mixture in 
this number, for Hooker in commenting on Presl’s genera says that his plant under that 
number is 7richomanes Javanicum. Presl later defends his genus in vigorous language 
and adds other species, and the genus was accepted by Van den Bosch. 
+ Abrodictyum Presl, Hymenophyllaceae, 20. /, 7. 1843. Monotypic; based on 
A. Cumingii Pres| (Luzon, Cuming, nos. 208, 358). 
} Didymoglossum Desv. Ann. Soc. Linn. Paris, 6: 330. 1827. Based on 
Trichomanes muscoides Sw. (first named) and seven other species. 
4 Meringium Presl, Hymenophyllaceae, 21. f/. 8, f. B. 1843. Based on two 
species, of which Af. Meyenianum Presl (Luzon, Meyen) is named as type. 
\| Sphaerocionium Presl, Hymenophyllaceae, 33. /. 4, f- Bs pl. 10, f. By eS 
1843. Based on Hymenophylium hirsutum Sw. (first named ) and numerous other species. 
