THE HIGHER CRYPTOGAMIA. 229 



the succeeding fronds are already formed whilst the fronds 

 are still in the condition of very young buds, inasmuch as 

 from the place where those vascular bundles which pass to 

 the two next adjoining older fronds bend aside to make 

 their way out of the stem, the cells of the bud-tissue are 

 transformed into cambium-strings as far as the younger 

 frond. Close under the place of insertion of the young 

 frond the two rudimentary vascular bundles unite to form 

 a single one (PL XXVI, fig. 9) which after passing through 

 the stipes for a short distance splits again into two (PI. 

 XXVI, figs. 10, 11). A vascular bundle passes to the 

 first frond from the fifth and sixth, and to the ninth from 

 the sixth and seventh, and so on. Thus the vascular bun- 

 dles of the young stem represent in their entirety a tubular 

 net, with rather wide meshes,* from whose angles, simple 

 vascular bundles pass off to the fronds. A transverse 

 section of the stem of a seedling of about a year old 

 exhibits five vascular bundles enclosing a pith. 



In the second year the plant develops itself much more 

 vigorously. Its fronds attain a foot in length ; their 

 arrangement proceeds normally according to the \% arrange- 

 ment. Henceforth several vascular bundles occur in each 

 stipes. In old vigorous individuals as many as five pass 

 from the knot of vascular bundles which corresponds with 

 the place of insertion of each frond. The lowest and most 

 vigorous of these bundles which, as it originates out of the 

 lower angle of the knot of vascular bundles, corresponds 

 with the single bundle of the fronds of the one-year-old 

 plant passes near the hinder surface of the stipes, and 

 divides into two close above the place of attachment of the 

 frond to the stem, at the place where the protuberant en- 

 largement of the stipes, characteristic of Aspidium filix-mas, 

 begins (PI. XXVII, fig. 6). Mature plants produce roots 

 exclusively from these two vigorous bundles of the stipes. 

 The stem, which in the first year of the germ-plant sends 

 out all the roots, afterwards ceases to produce any. Prom 

 the side angles of each knot of vascular bundles of the 

 stem two thin vascular bundles pass off into the frond, and 



* Mohl, ' Vermischte Schriften,' p. 115. 



