. Our native ferns and their allies [microform] : with synoptical descriptions of the American pteridophyta north of Mexico. Ferns; Fougères. FRUCTIFICATION IN FERNS. 13 3Q|b. Campylon«uron has areolae, each usually bearing two sori; they are found between the parallel primary veins which extend from the midrib to the margin. 31. Qymnopterls.—In this genus the sori follow the course of the veins, and consequently vary with the venation, being simple, forked, pinnated, or anastomose with each other. The sori arc non-indusiate. 32. Nctholaena.—In the cloak-ferns the sori are marginal, and provid
. Our native ferns and their allies [microform] : with synoptical descriptions of the American pteridophyta north of Mexico. Ferns; Fougères. FRUCTIFICATION IN FERNS. 13 3Q|b. Campylon«uron has areolae, each usually bearing two sori; they are found between the parallel primary veins which extend from the midrib to the margin. 31. Qymnopterls.—In this genus the sori follow the course of the veins, and consequently vary with the venation, being simple, forked, pinnated, or anastomose with each other. The sori arc non-indusiate. 32. Nctholaena.—In the cloak-ferns the sori are marginal, and provided with no indusia. This genus is linked very closely to Gymiiopteris on one hand and to some species of Cheilanthes on the other. From the latter it is separable only by the ab- sence of the marginal indusium; the two are likely to be con- founded by beginners. 33. Cheilofframma has simple fronds, the fructification in a continuous sub-marginal line near the apex of the frond. 34. Vittaria.—This peculiar genusoccupies a somewhat in- termediate position between the indusiate and non-indusiate genera, and while usually associated with the latter has consid- erable claim to be ranked with the former. The fronds are nar- row and grass like, bearing the sporangia in an intramarginal groove, often more or less covered by the inrolled edge of the frond. The venation Is very obscure. 35. Adiantum (Fig. 5).—The maidenhairs have a peculiarly smooth foliage, and usually possess no midvein. The veins are usually flabellate, and after forking one or more times bear the sori at their extremities. The margin of the frond is reflexed, thus forming an indusium which bears the sporangia on its under surface. p«g. s-—a segment of ,_. ,. _ , . Adiantum, showine the 36. Pterls (Fig. 6).—In this genus, sori covered by indusia formed by reflexions of the. now excluding the common brake, the mI^lno?^thefrond--From otherwise free veins are united by a fili- Le Maout and Decaisne form re
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