2. POLYPOBIACEJE. 



as numbered in the key. Gymnopteris he inchides iu the Aspidiece, whereas 

 Beddome, rightly I think, shows it as numbered below. As regards the position 

 of several species of Nephrodium, included by several botanists under Polypodium 

 merely on account of the absence of indusium, I have had no hesitation in placing 

 them in Nephrodium as is done by Diels and Beddome, and I have not shown 

 these twice. 



I. Sori confined to the venation, not occupying the whole 



surface of whole or part of the frond (Genera 1-23) : — 



A. Indusium present, or margin of frond modified or 



recmved over the sori, or if indusium absent then 



fronds not articulating with the rhizome (Genera 



1-19) :— 



1. Sori round. Indusium round or neplu-oid or half- 



orbicular, extrorse or peltate and opening on all 

 sides, sometimes rudimentary or 0. (Genera 

 1-8) :— 



a. Sori dorsal or terminal on the veins, attached by a 



point, by the centre or a sinus. Leaf-margin lui- 

 modified. Stipes never articulate (Aspidice): — 

 i. Indusium nephroid or rudimentary or 0. 

 Venation pinnate, often herring-bone type : — 

 Frond simply pinnate (in our species). One or 

 more veins from the costule uniting with 

 those from the adjacent costule . . 1. Nephrodium. 



Frond 1-more pinnate. All veins free . . 2. Lastrea. 



ii. Indusium peltate or, if 0, then venation reti- 

 culate : — 

 t Frond compound, not or only slightly dimor- 

 phic : — 

 Venation pinnate, free. Teeth of lobes 



spinulose 3. Polystichum. 



Venation copiouslv anastomosing with free 



included veinlets 4. Aspidium. 



tt Frond simple,- dimoi-phie. Fertile much 

 contracted. (Sori occasionally scattered 

 over the back of a normal frond) . . 24. Gymnopteris. 



b. Sori mostly terminal on the veins. Indusium 



extrorse attached by a broad base or partially 

 adnate to the leaf margin, which is often 

 modified. Fronds 1-more pinnate, sometimes 

 articulate to rhizome. Veins free {Da vulliece) : — 

 i. Sori not confluent. Indusium attached by a 

 broad base : — 

 Stipes inarticulate, pinnae articulate. Frond 



simply pinnate, with cretaceous dots . 5. Nephrolepis. 



Stipes articulate, pinnae inarticulate. Frond 



3-4-pinnatifid, without cretaceous dots . 6. Humata. 

 ii. Indusium adnate on three sides to the frond. 

 Frond inarticulate : — 

 Fronds 2-ranked on the creeping rhizome. 



Eeceptacle distinct . . . .7. Microlepia. 



Fronds tufted. Sori marginal. Receptacle 



not evident . . . . . .8. Odontosoria. 



2. Sori oblong or linear, straight or curved. Indusium 



present or margin of frond simulating an 

 indusium : — 

 a. Sori lateral on the fertile veins. Indusium 

 introrse or if double also extrorse. Veins, at 

 least the barren ones, free (Asple niece) : — 

 i. Sori attached to and parallel to the veins. 

 Veins all free : — 

 t Sori short, one only to a vein : — 



Indusium straight linear or oblong. Scales 



of stipes with thick-walled cells . . 9. Asplenium. 



Indusium usually curved or hooked and 

 overlapping the vein. Scales of stipes 

 with very thin walls . . . .10. Athyrium. 



1184 



