246 HOFMEISTER, ON 



vascular bundles in the stem. Asplenium filix-femina is 

 distinguishable by the more slender form of the terminal 

 bud, the growth of which in thickness terminates at the 

 fourth set of cells, (reckoning downwards and sideways from 

 the apical cell), the produce of one of the cells of the second 

 degree, so that the frond-less apex of the stem is elevated 

 considerably above the earliest rudiments of the fronds 

 (PI. XXXIII, fig. 2). A further peculiarity of this plant is 

 that only one vascular bundle enters each stipes from the 

 upper angle of each knot of vascular bundles. For a con- 

 siderable distance this bundle is simple ; it then divides 

 into two, and further up into several strings. The status 

 which in Aspidium jilix-mas only occurs whilst the plant is 

 young, that is to say only in the one year old plant, is main- 

 tained here during its whole life. Underneath the place 

 where the vascular bundle of the stipes exhibits its first 

 ramification, one root is normally produced ; each frond 

 has only one, which is developed in a plane passing through 

 the median line of the frond. This circumstance greatly 

 facilitates the investigation of the earliest stages. In well- 

 made longitudinal sections, close outside the rudimentary 

 vascular bundle of the frond, there may be seen the primary 

 cell of the appurtenant root, by the multiplication of which in 

 the manner pointed out in Aspidium flix-mas, the root-cap 

 and the permanent cylindrical portion of the root are pro- 

 duced (PI. XXXIII, figs. 4, 5). The tissue of both halves 

 of the growing root, as well as the cells of the root-cap, are, 

 whilst in this early state, in intimate parenchymatal con- 

 nexion with the cortical cells of the stipes. Afterwards, 

 shortly before breaking forth from the hind surface of the 

 stipes, the boundary between the root-cap and the cells be- 

 fore it becomes sharply defined (PI. XXXIII, fig. 6) with- 

 out however any rupture of the tissue, or the appearance of 

 any inter-cellular space. The few cellular layers of the 

 stipes anterior to the apex of the young root, are gradually 

 displaced and dissolved, not broken through; the cuff- 

 like margin, which is formed from the cellular tissue of the 

 mother-portion of the plant, and which is so remarkable on 

 the adventitious roots of many Monocotyledons, is wanting 

 here. 



