242 



THE BOOK OF CHOICE FERNS. 



numerous roundish, oblong, or kidney- shaped marginal patches. This group, 

 probably the most important in point of numbers, is divided into three sections, 

 as follows : 



Section I. — Plants with segments (leaflets) not dimidiate (fully 

 developed on one side only, scarcely if at all on the other), but of 

 regular expansion, extending on both sides alike and having two more 

 or less distinct opposite rows of sori. Of this section A. intermedium 

 is a very good illustration. 



Section II. — This is composed of species with segments (leaflets) 

 dimidiate, the stipes (stalks) naked and polished, and is well represented 

 by A. diaphanum, known in commerce as A. setidosum. 



Section III — The' plants composing this section have, like those of 

 the preceding one, their segments dimidiate, but their stipes are 

 pubescent (downy), as those of A. Henslovianum. 



4. — Oligosorous (Ol-ig-os-or'-ous), or " Few-sori-bearing Group," composed 

 of plants with fronds once or more pinnate, and the fruit disposed in con- 

 tinuous or slightly interrupted marginal lines. This group is also divided 

 into two sections, according to the disposition of the sori. 



Section I. — This comprises subjects in which the segments are provided 

 with a line of fruit on both sides, and are, therefore, not dimidiate, as in 

 A. peruvianum for example. 



Section II. — The plants of this section have their segments dimidiate, 

 with the line of fruit altogether absent from the lower margin, as in 

 A. pulverulentum. 



5. — Capillus- Veneris (Cap-il'-lus-Ven'-er-is). All the subjects belonging 

 to this numerically very important group have their fronds at least bipinnate 

 (twice divided to the rachis or midrib), their segments flabellato-cuneate 

 (rounded at the top and wedge-shaped at the base), with the petiole (stalk) 

 situated near the centre, and the sori kidney- shaped. These various characters 

 are most distinctly shown in A. Capillus- Veneris and some of the Tropical 

 American species with most minutely-divided fronds, such as A. Wagneri 

 (known in commerce as A. decorum), A. Moorei (known in gardens as 

 A. a?nabilis), A. concinnum, A. tenerum, &c. 



6. — Scandentes (Scan-den'-tes), or " Climbing Group." In the few species 

 belonging to this group, the plants are provided with stems or elongated stipes 



