123 175 



4. Pinnæ 15 — 20 cm long by 2 — 2' a cm broad, thinly herba- 

 ceous 199. D. urens Ros. 



2. Rhizome creeping. 



3. Rachis not or very indistinctly scaly. Basal scales ferruginous, 

 narrow-acuminate, as a rule hairy. 

 4. Lower pinnæ not shortened. 



5- Basiscop lower segments of lower pinnæ not or slightly 

 reduced. Pinnæ seldom more than 10—15 cm long, 2 cm 

 broad; veins 6 — 10-jugate. 



6. Veins not prominent beneath. Lower pinnæ not nar- 

 rowed towards their base. No scales on rachis and 



costæ 192. D. normalis C. Chr. 



6. Veins more or less prominent beneath. Lower pinnæ 

 more or less narrowed towards their base. Rachis 

 and costæ beneath often with small hairy scales. 

 7. Lamina herbaceous or membranous without a di- 

 stinct terminal pinna. Veins not close. 

 8. Underside decidedly pubescent. Cuba and Cen- 

 tral America 193. Ü. augescens (Lk.) C. Chr. 



8. Underside practically glabrous. Argentina and 



Paraguay 194. /J. Berroi C. Chr. 



7. Lamina coriaceous with a distinct terminal pinna. 

 Veins close, the lower 4 connivent to sinus. Pinnæ 



generally long and narrow 195. D. serra (Sw.) O Ktze. 



5. Basiscop lower segments of lower pinnæ abortive or per- 

 fectly obsolete. Pinnæ up to 50 cm long by 3 — 4 cm 

 broad. Veins 15 — 20-jugate, the lower 2 — 4 connivent to 



sinus 196. D. oligophylla Maxon. 



4. Lower pinnæ shortened. Leaf throughout much hairy. 



Lamina firm often coriaceous. Habit of D. patens. 198. D. Bangii C. Chr. 

 5. Lamina thinly herbaceous, the hairs burning. Habit of 



D. mollis 199. D. urens Ros. 



3. Rachis and stipe densely scaly 197. D. Tuerckheimii (Donn. Smith) C. Chr. 

 1. Basal tertiary veins normally united in the leaf-tissue, sending an ex- 

 current branch to the sinus. 



2. Sporangia glabrous. Aërophore none. No veins connivent to sinus. 

 3. Rhizome oblique or short-creeping with narrow, ferruginous 

 scales at the apex. Costæ beneath without scales. Lamina gene- 

 rally narrowed downwards. Pinnæ sessile. 



4. Leaf herbaceous. Rachis slender 200. D. mollis (Jacq.) Hier. 



4. Leaf firm to coriaceous. Rachis strong, quadrangular, very 



hairy 198. D. Bangii C. Chr. 



23* 



