*X COHPKRSnjM. 



antheridia aad archegonia. Sporangia dorsal (on the under surface) or marginal 

 on leafy fronds, rarely in spikes or panicles. (10 Families). 



SUBORDER 11. HYDROPTERIDES (Heterospore Fi- 



licales, Water-ferns). Spores dimorphous, macrospores and microspore^, both 

 developing more or less rudimentary prothallia, those of the macrospores bear- 

 ing archegonia and those of the microspores antheridia. Sporangia enclosed 

 in metamorphosed fronds forming 1 — 4-celled, globose or ellipsoidal sporocar- 

 pia. (2 Families; not treated with in this work). 



FILICES. 



See Supplement 1, p. 9 —13. 



Capsules (sporangia) 1-celled, sessile or stalked, usually membranaceous, 

 dorsal or marginal, encircled by a complete or incomplete, ± vertical or 

 horizontal, jointed, elastic ring (annulus) and opening by a stomium at right 

 angles to the ring, collected in clusters (sori) of a deBnite but varied form 

 with or without a covering (iodusium), or crowded densely over the paren- 

 chyma, sometimes scattered, spicate or paniculate; or the capsules have the 

 ring obsolete, or none, or the ring is confined to the apex of the capsule, 

 where it forms a longitudinally striated crown bursting vertically; or the 

 capsules are sunk in many-celled, fleshy or corky receptacles of varied forms, 

 opening by pores or clefts on the upper or inner side. Spores minute, vari- 

 ous in form, mostly ellipsoidal, bilateral, tetrahedral or globose, and in in- 

 termediate forms. 



eL<ASSI I. PL..%IllTHAL.L.OSAE. Prothallium flat or filiform, 

 green, entire or variously incised or branched. 



Series i. Annulatae. Sporangia with a complete or incom- 

 plete ring consisting of a close or open row or a group of thickened 

 cells. 



FAMILY I. CYATHEACEAE. Ring complete, subvertical. Indusium 

 wanting or present, but then neither umbrella-shaped nor linear. 

 Caudex arborescent in the full-grown plants. 



