214 HOFMEISTER, ON 



stem becomes forked by the division of its punctual vege- 

 tationis. Eacli branch of the fork increases rapidly and 

 considerably, and about equally, in thickness. The first 

 frond of each is usually situated to the right hand (PI. 

 XXIX, figs. 10, 11). From this time forth the course of 

 the vascular bundles of the stem is a compound one. The 

 lateral opening of the central vascular bundle becomes 

 enlarged (PI. XXIX, fig. 8). Its upper half is soon sepa- 

 rated from the lower; the vascular bundle is prolonged, 

 whilst the tissue of the bud of the stem remains paren- 

 chymatal. The stem has now two flat vascular bundles 

 (PI. XXIX, fig. 9) parallel to the axis, which here and 

 there split into thinner forked branches which soon unite 

 again (PL XXIX, fig. 9'). When the furcate shoots 

 have attained a length of about three inches, and their 

 transverse diameter is about two lines wide, the two large 

 vascular bundles send out less vigorous bundles which take 

 a direction nearer to the bark, and of which the uppermost 

 one, which passes above the axile bundles, is somewhat more 

 fully developed, and is about equal in breadth to the latter 

 (PI. XXIX, figs. 12, 13). The cortical vascular bundles 

 anastomose in the vicinity of the place of insertion of each 

 frond, and thus form a hollow cylindrical network of elon- 

 gated meshes. But no connecting branches between them 

 and the axile bundles are to be found anywhere in the 

 stem. The latter follow an entirely isolated course within 

 the creeping steins ; ramifications from them enter the 

 fronds, and it is only these ramifications which are 

 met inside the stipes by ramifications from the cortical 

 vascular bundles. Roots originate only from the latter 

 bundles. 



The stems of fully grown plants exhibit, in all essential 

 points, the same distribution of vascular bundles. The 

 number of the peripheral ones amounts to as many as 

 twelve. The two uppermost of the latter are blended to- 

 gether for the greater part of their course, and thus form a 

 wide bundle, which lies in the same vertical plane as the 

 primary axile bundles. Two masses of cells almost 

 parallel to these primary vascular bundles, and situated 

 between them and the peripheral vascular bundles, become 



