332 



VASCULAR CRYPTOGAMS. 

 Key to Natural Orders. 



1. Small floating plants or land 



plants with quadrifoliate 

 leaves ... 

 Land plants, never with quadri- 

 foliate leaves .. . 



2. Stems hollow, without leaves, 



branches whorled with sheaths 

 at the joints ... 

 Stems solid, with leaves (except 

 Psilotum), branches not whorled 



3. Leaves with copious and often 



complicated venation or not 

 scale-like and imbricate 

 Leaves scale-like, imbricate, with 

 a single central vein ... 



4. Leaves all round the stem and 



usually uniform 

 Leaves in four rows and dimor- 

 phous ... 



5. Rhizocarpeae (p. 359). 

 2. 



2. Equisetaceae (p. 357). 



3. 



L Filices. 



4. 



3. Li/copodiaceae(p.357). 



4. Selaffinellaceae{p.358), 



4. 



1.— FILICES. 



Key to genera. 



Capsules with a complete ring . . . 

 Ring of capsules incomplete or 0, 



climbing or aquatic fern or 



fronds over 6 feet long or 



fertile and leafy parts distinct 

 Capsules with a transverse ring ; 



creeping or translucent fern 

 Capsules with a vertical ring 

 Involucre absent ; stem dichoto- 



mous ; creeping fern ... 

 Involucre cup-shaped ; stem not 



dichotomous ; translucent fern 

 Hair-like receptacle prolonged 



beyond the involucre ... 

 Receptacle not prolonged beyond 



the involucre ... 



5. Involucre present ... 

 Involucre absent ... 



6. Involucre holding Ihe 



against the fronds 

 Involucre keeping the 

 free from the fronds , 



7. Trunk spiny 

 Trunk not spiny ... 



capsules 

 capsules 



2. 



31. 



3. 

 5. 



Gleichenia (p. 334). 



4. 



Trichomanes (p. 335). 



Hymenophyllum. (p. 

 335). 



6. 

 22. 



8, 



7. 

 Cyathea (p. 334). 

 Dicksonia (p. 335). 



