242 The Ottawa Naturalist. [Feb. 



kind of rhizome which has been called a "pseudo-rhizome," and 

 is known from many plants, especially with epigeic cotyledons, 

 Galium for instance. To this type belongs, also, Aristolochia 

 Serpentaria L. (Fig. 28), where the cotyledons remain enclosed 

 within the seed; w^here the primary root is well developed, but 

 where there is no hypocotyl, and finally where the vegetative 

 reproduction is effected by only one bud arising from the axil 

 of one of the cotyledons. Aristolochia differs from Phrym'a in 

 another respect, by the first leaf succeeding the cotyledons being 

 scale-like, instead of showing approximatelv the same structure 

 of the final leaves as in Phryma. 



The most frequent type is, however, the one in which the 

 cotyledons may or may not remain within the seed, and where 

 the primary root develops as a strong persisting root supporting 

 the aerial, woody stem, as in many trees of various genera. 

 Sassafras, Lindera, Quercus, Aesculus, Prunus, etc. In these 

 the primary shoot remains as the only one, no cotyledonary buds 

 being developed, and the earlie.st leaves may possess a distinct 

 blade, or they may be developed merely as small, scale-like organs 

 as in Carya, Jiiglans, Sassafras and others. 



Finally may be mentioned the very singular seedlings of 

 Persea gratissima Gartn., and Garcinia Cockinchinensis Choisy. 

 In the former the cotyledons are very large, and remain enclosed, 

 each subtending an axillary bud, ready to develop, if the plumule 

 should become injured. The plumule bears in this species two 

 pairs of opposite leaves Vvdth petioles and small blades, while 

 the succeeding five or six leaves are almost scale-like, and very 

 different from the ultimate. Persea thus demonstrates the fact 

 that in seedlings with enclosed hypogeic cotyledons, there may be 

 an alternation of various forms of leaves, while in Juglans and 

 Carya, for instance, all the first leaves are scale-like. 



Still more remarkable is the seedling of various members of 

 the GuitifercB, especially of Garcinia Cockinchinensis Choisy. 

 No cotyledons are developed, and the primary root soon dies 

 off being replaced by a few very strong secondary roots, develop- 

 ing from the apex of the very large, bean-shaped hypocotyl. In 

 this type the hypocotyl contains a broad parenchyma traversed 

 by numerous resiniferous ducts, and filled with deposits of 

 starch. 



These dicotyledonous seedlings, thus, illustrate no small 

 variation in respect to the development of cot3dedons, hypocotyl, 

 and root ; furthermore, in regard to the young foliage succeeding 

 the cotyledons. We have seen that in many trees, for instance 

 Carya. Sassafras.Que^-cus, etc., the ea.v\iest foliage consists merely 

 of scale-like leaves, while in Liriodendron . Catalpa Platanus 



