Asplenium.] FILICES. 585 
primary veinlet, crossing it at the upper end. Involucre shaped like 
the sorus, attached to the back of the vein, in single sori opening toward 
he costule and apex, in double sori opening also toward costa and margin. 
Spores seer Stipes continuous with the root-stock, holding at its base 
two flattened fibro-vasal fascicles which unite in various ways in their 
earn : 
A large genus, spread over the whole globe 
Veins co ar by an ee ee nerve; frond simple 
(Tham wis) . Cy aaa 1. A. nidus. 
Veils fre 
Sori sine: riding with a simple involucre (Ewasplenium) : 
Frond pinnate, pinnae subentire: 
innae n not an uch longer than broad: 
Stipes 
Petes suborbicular 2. A. trichomanes. 
Pinnae rhomboida 
Pinnae with a not ‘excurrent pron stone omnes sori 
often single om a pinna; frond n g below 3. A. monanthemum. 
Pinnae with an excurrent midrib or anata: frond 
neate at the Boa 4. A. normale. 
Stipes green or pale bi 
Pinnae ings with a deliqnescent rib; the sori 
flabe Mat 6. A. fragile. 
Pinnae ovatetanceotate, with an excurrent rib; the sori 
inn nm both sides 7. A. erectum. 
Pinnae ee ike ate: 
— green when fresh, dull gray when dry: 
Vrond, pinnate to the apex; sori at uniform angles 
of 30—40°: 
Pinnae PRL Ee /2f 
Frond iatg peo pinnae more than 12 0n 
a — e. 9. A. Kaulfussii. 
d pale, thin; pinnae less than 9 on aside 10..A. en 
Pinnae less than 1/2’ broad, 11. A. Mannii. 
op lmaeaae at the apex; oe at sori gradually 
g toward the auricul 15. A. pseudofalcatum. 
Stipes pane pc glossy; pinnae inciso - -serrate at acute 
angles : 
Pinnae linear-lanceolate, less than 1/2‘ broad 
r- 
elo penn closely contiguous to the midrib; po 
-green 19. A. contiguum. 
eri oblong-lanceolate, 1/a—1! proad; sori imbricate, 
diverging; frond olivaceous 22. A. caudatum. 
Pinnae ovate-lanceolate; upper basal sori irradiating 
toward the margin A 
Pinnae Seite enansuata sori short and few in one : 
al distances between rib and m a 20. A. Knudsenii. 
Stipes drieajsrsereaaa glossy. ; 5. A. resectum. 
Frond pinnate; pinnae pinnatifid: 
Sori dareoid, cat al when only one on a — 
Pinnae not longer than 11/2’ 
Pinnae 4—7’ long — dareoid varieties of nos. 9, "10, 1. 
Sori not marginal: 
— or segments short, truncate, subequal ; sori along 
midrib: 
. nitidulum. 
7. A. erectum, var. , {. 
. horridum 
‘ caudatuss, var. 
pe pe 
stipes ered 
to 
a) 
