3 8 4 
FILICINEAE LEPTOSPORANGIATAE 
indusium, with complete transverse annulus and longitudinal 
dehiscence; creeping rhizome; leaves dichotomous). 
3. Hymenophyllaceae (sporangia with oblique or transverse com- 
plete annulus, opening by longitudinal fissure; they are 
marginal with a cup-shaped indusium; stem slender, often 
creeping; mesophyll usually one cell thick). 
4. Schizaeaceae (sporangia sessile with cap of thick-walled cells at 
apex instead of a ring-like annulus, and with longitudinal 
dehiscence; indusium or none; sporangiferous pinnae usually 
in spikes or panicles). 
5. Cyatheaceae (sporangia shortly stalked with complete oblique 
excentric annulus ; sorus naked or with cup-like indusium ; 
mostly tree-ferns). 
6. Polypodiaceae (sporangia stalked with vertical incomplete annu- 
lus, and dehiscing transversely). 
For relationship, see art. Filicineae. 
2. Heterosporous F. L. ( Hydropterideae or Rhizocarpae), The 
two orders of which this group is composed, though they have much 
in common, are almost certainly derived from different stocks amongst 
the ferns. For details reference should be made to the orders. 
As in the homosporus forms, so here the embryo gives rise 
directly to a new leafy plant. This is usually aquatic in habit, and 
exhibits a creeping stem with a dorsiventral arrangement of the leaves. 
Roots may or may not be formed. The stem grows by means of an 
apical cell. The sporangia are enclosed in capsular structures termed 
sporocarps. In the Salviniaceae this body contains one sorus only, in 
the Marsiliaceae more than one. The sorus in the former is composed 
of one kind of sporangium only, in the latter usually of both. The 
spores germinate in water ; the megaspore gives rise to a small green 
female prothallus which remains enclosed in the burst spore. Its free 
surface bears a few archegonia. The microspore gives rise (some- 
times without escaping from the sporangium) to a rudimentary male 
prothallus and an antheridium. From the latter the spermatozoids 
escape and swim to the female organ. 
Classification : 
Order 1. Salviniaceae (sporocarps unilocular). 
2. Marsiliaceae (sporocarps plurilocular). 
For general relationships, see Filicineae. 
Fimbristylis Vahl. Cyperaceae (1). 200 sp. chiefly trop. 
Fistularia Linn. = Rhinanthus Linn. 
Fitzroya Hook. f. Coniferae (Arauc. 2a; see C. for genus characters). 
2 sp. Chili, Tasm. 
Flacourtia (Comm.) L’Herit. Flacourtiaceae. 15 sp. trop. As., Afr. 
F, Ramontchi L’Herit., the Madagascar plum, and others have 
edible drupes. 
