164 J. SMITH ON THE GENERA OF FERNS. 



cies in which the lower venules next the midrib only anas- 

 tomose; but this seems to me not sufficient reason to war- 

 rant their separation from Litobrochiaj especially as they 

 differ in no respect in habit from many species of that genus. 



59. LoNCHiTis, Lin7i. J. Sm. 



Venation ret\c\}]a\.e(i ; areo/es unequal ; sporatigia produced 

 on the apices of 4 — 5 convergent venules which terminate m 

 the sinus of the lacinise, forming oblong or linear-arcuate 

 marginal sori. Indusiwn linear. 



Fronds 2 to Qfeet Idgh, pinnate or hipinnate, pinnce sinuous 

 or pinnatifid, usually pubescent. 



Species. 1. L. aurita, Linn. 2. L. pubescens, Willd. 3. 

 L. glabra, Siv. Illusf. Plum. Fil. t 17. Schott, gen. fit, t. 

 15. Hook. Gen. Fil. f. 68. A. 



Obs. The few species which constitute this genus agree in 

 habit with the preceding genus, and differ only in the 

 sorus being situated in, and not extending much beyond, the 

 curve which is formed by the sinus of the lacinia*, and by being 

 so situated assuminij the form of a segment of a circle; whereas 

 in Lifobrochia, the sori occupy more or less of the sides of 

 the laciniae. By restricting Lonchitis to the above character 

 excludes from it the L. hirsuta, and L. pedata of Linnseus, 

 the first being a lAtobrochia, and the other a true Pterin. 



60. Pteris, Linn. J. Sm. 

 (Pteridis sp. Presl. Allosore® sp. Presl.) 



Veins forked ; venules direct, their apices combined by a 

 transverse sporangiferous receptacle, constituting a linear 

 continuous or interrupted marginal sorus. Indusinm linear, 

 its base often sporangiferous. 



Fronds varying from a few inches to 10 feet highj and from 

 pinnate to decompound, the ultimate pinnce usually lobed or 

 equally pinnatifd, smooth, rarely pubescent. Sori continuous or 

 occupying the sides of the lacinicB only. 



Examp. 1. P. longifolia, Linn. 2. P. costata, Bory. S* 

 P. amplectens, Wall. 4. P. crelica, Linn. 5. P. umbrosa, 



