70 



ary one, St.-, which has been developed from the axil of the 

 first leaf. The whole plant was glandular-hairy, like the 

 germinating plantlet. 



Potentilla Canadensis. 



The cotyledons of this species are entirely under ground, 

 short-petioled, with the blade ovate and rather fleshy. The 

 hypocotyl is short and covered with minute glandular hairs, 

 as are also the cotyledons, and the primary root is strongly 

 developed, long, and branched at an early stage. This is to be j^ 

 seen in Plate X, Fig. 53, where we also see the rapid develop- 

 ment of the plumule into an axis, which is runner-like, ascend- 

 ing with several leaves, of which the first one differs from the 

 final one in being almost kidney-shaped, with the margin 

 coarsely serrate ; the other leaves are palmately trifol- 



10 



late 



1 





\ 



1 



* 



V 



When the plant has attained its full growth, a rhizome is 

 to be observed, which is often tuberous and with the primary 

 root still persisting (Fig. 54). 



SAXIFRAGACEyE. 



Saxifraga Virginiensis . 



The seed of this species germinates early in the month 

 of March, and the germinating plantlet is especially charac- 

 terized as having short-petioled and broadly ovate cotyle- 

 dons, which are above ground, a distinct, erect hypocotyl, 

 and a long, filiform primary root (Plate X, Fig. 55). When 

 the leaves begin to unfold the hypocotyl bends downward to 

 the ground after having developed two or three secondary 

 roots that very soon surpass the primary one. The first leaves 

 are broadly ovate or elliptic, sparingly hairy, with stellate \ 



hairs on the upper surface of the blade, and the petiole is 

 slightly pubescent (Figs. 56 and 57). When the plant 

 grows older, the primary root disappears entirely and is re- 

 placed by several secondary roots, and in Fig. 58 we see the 

 beginning of the formation of the very short, vertical rhizome 

 that is provided with a few roots and is represented by the 

 superior part of the hypocotyl. Five leaves were developed 



> 



I 



*• 



