FILICES. (FERNS.) 
621 
* (Polypodies.) Fruit-dots without a special indusium (roundish). 
h- Fertile fronds like the sterile, leaf-like, the margins not revolute. 
1. Polypodium. Fruit-dots scattered on the back, separate. 
— Fertile fronds contracted, revolute, forming a general involucre. 
2. Struthiopteris. Fruit-dots borne on the 5 pinnate veins of each 
lobe of the linear necklace-form pinnae, soon confluent over 
the w hole under surface. 
3. Allosorus. Fruit-dots on the simply forked veins, soon later¬ 
ally confluent, forming a broad intramarginal line, concealed 
under the reflexed margin. 
* * (PterIdeje.) Fruit-dots covered by a special indusium pro¬ 
duced from the outer side and free on the inner (next the midrib 
or axis of venation), either marginal or on cross vemlets parallel 
with the midrib, therefore transverse. 
- Fruit-dots marginal, laterally confluent or separate, borne on the 
free terminations of the forked direct veins (no cross vemlets). 
4. Pteris. Indusium linear, continuous, bearing the sporangia of the 
laterally confluent fruit-dots next its line of attachment. 
5. Adiantum. Indusium kidney-shaped, roundish, or oblong (usu¬ 
ally appearing as the reflexed margin of a lobe of the frond), 
bearing the sporangia on its under surface on 2 or more veins. 
6. Cheilanthes. Indusium kidney-shaped, receiving a single vein 
which is fruit-bearing at its extremity. 
Fruit-dots parallel and near the midrib, borne on transverse anas- 
tomosing veinlets. 
7. Woodwabdia. Indusium oblong or linear. Marginal veinlets free. 
. . . (Aspleui**.) Fruit-dots elongated, borne on the baek of the 
frond oblique to the midrib (not parallel W .th t‘ nor he 
ffin^ each covered by a special indusium which is free along 
edge’,and attached longitudinally to the fertile veinlet on the other. 
.. Veins reticulated, except next the margin. 
8. Camptosobus. Fruit-dots irregularly scattered over the frond. 
Veins forked and free, none of them reticulated. 
9. Scolopendbium. Fruit-dots in pairs laterally “" flue t ^ , “ einlets .' 
10. Asplenium. Fruit-dots separate, on the uppers 
. , (D.cksonie*.) Frnit-dot. marginal, on the termination of a 
..... (AsrinnU.) Fruit-dots borne on the furnished 
round, rarely oblong and then p ““ /^"hooded indusium, but 
with a special orbicular, kidney-shaped, or boon 
no accessory proper involucre. 
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