THE HIGHER CRYPTOGAMIA. 225 



treme rapidity, and produces an abundance of roots. Un- 

 branched terminal shoots of this kind, of from six to ten 

 inches long, are not rare. In these shoots the lower part of 

 the annular wall which surrounds the terminal bud, pro- 

 trudes itself forward in a labiate form, so that it eventually 

 lies upon the upper surface of the gradually flattened 

 shoot (PI. XXX, fig. 4). The distribution of the vascular 

 bundles in these unbranched, frond-less ends of shoots, 

 exactly corresponds with that of the frond-bearing stem ; 

 a convincing proof that the arrangement of the vascular 

 bundles in the stem is not dependent upon the position of 

 the appendicular organs, or the number and form of the 

 bundles occurring in such organs.* 



The two wide axile vascular bundles are entirely devoid 

 of branches in each joint of the sympodium. At each fork 

 they send out into the more delicate shoot vigorous branches 

 which constitute the axile vascular bundles of the latter 

 shoot. I have met with sympodia four feet long devoid of 

 fronds. The distances between two furcations are very un- 

 equal, and manifestly dependent upon the amount of 

 nourishment being greater or less. The entire ramification 

 of the plant, so far as it depends upon the furcations of the 

 terminal buds, and the position of the fronds on these 

 ramifications, correspond entirely with the pinnations of the 

 blade of the frond. These latter are only distinguishable 

 in their first rudiments from the furcations of the terminal 

 bud, by the upward direction of the growth of the frond : 

 they do not differ in their cell-succession. 



Buds from which new shoots may be, and are developed, 

 are found in Pteris aquilina only on the under side of the 

 stipes ; sometimes low down, sometimes higher up. Some- 

 times they appear so early and are so near the place of in- 

 sertion of the frond that at first sight they appear to belong 



* The same conclusion may be drawn from the condition (observed by H. v. 

 Mold, 'Verm. Schriften,' p. Ill,) of the upper ends of the vascular bundles of 

 all ferns, especially of those with creeping stems and bilinear phyllotaxis (see 

 PI. XXXV, fig. 4) : although the relations in question do not elsewhere stand 

 out in so marked a manner. The conclusion given above would be valid even 

 if the objections raised by Mettenius against my views of the mode of ramifi- 

 cation of Pteris aquilina ('Abhandl. K. Sachs Ges. der Wiss.,' b. yii, p. 

 C21,) could be maintained, which, however, as I shall hereafter show, is not 

 the case. 



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