1909] Seedlings of Ph^nogamous Plants. 241 



Very remarkable is the seedling of Jatropha multifida L., 

 of which the cotyledons are distinctly petioled and by a long 

 hypocotyl raised above ground, but of which the cotyledonary 

 blades remain enclosed by the seed. In certain species of 

 Clematis {C. recta) the cotyledons are normally hypogeic, but 

 at times become epigeic. 



Hypogeic cotyledons may remain enclosed by the seed all 

 the time, or they might become freed from this and appear then 

 as a pair of small, fleshy, paje leaves. Herbs as well as trees 

 exhibit this manner of germinating, and characteristic of all is 

 that the function of the cotyledons is only to be the bearers of 

 reserve food-substances. The relative development of the 

 primary root is somewhat different ; furthermore, the hypocotyl, 

 and the petioles of the cotyledons. 



An interesting type is represented by Megarrhiza Calif ornica 

 Torr. In th'is plant the primary root does not commence to grow 

 until the cotyledonary petioles have buried themselves deep 

 in the ground, and these petioles are not onh" very long, but they 

 are, furthermore, united so as to form a long tube, clothed with 

 hairs which perform the same function as root-hairs. 



Another type is characteristic of certain aquatics, e.g. 

 Nuphar, Nymphcea and Victoria, in which the primary root 

 increases but very little in length during the first stages of 

 germination, its function becoming performed by a wreath of 

 very long root-hairs developing from the base of the root as soon 

 as the seed germinates. In Nehimbium, on the other hand, the 

 root stays rudimentary, and does not even produce the wreath 

 of hairs, so very characteristic of the others. 



Sometimes the hypocotyl is well differentiated as in 

 Sanguinaria Canadensis L. (Fig. 29), and we have here an 

 interesting type with a persisting primary root (at least for 

 some years), and a hypocotyl which by growing in thickness 

 becomes the first joint of the large, horizontally creeping rhizome ; 

 the fieshv cotyledons soon leave the seed, but without being 

 raised above ground. Furthermore, in this type the first leaf 

 succeeding the cotyledons develops already during the first year, 

 and shows the outline of the blade broadly cordate, and entire, 

 instead of being prominently lobed as the final leaves. In 

 Phryma Lcptostachya L. the cotyledons do not leave the seed, 

 and the hypocotyl is ver}' short ; the primary root develops as a 

 long, somewhat fleshy root, which persists for some years. 

 Phryma lacks a proper rhizome in the stricter sense of the word, 

 since the vegetative reproduction is simply secured by cotyledon- 

 ary buds in the first year, and later on by buds, which develop in 

 the axils of the basal, scale-like leaves of the aerial shoot ; it is a 



