168 The Ottawa Naturalist. [Dec. 



cotyledon becomes freed from the seed and stretches itself to- 

 wards the light. The plumule is located at the base of i the 

 cotyledonary sheath and develops mostly only one green leaf 

 during the first season. This manner of germinating is known, 

 also, in Sisyrinchium and several Liliacece, for instance many 

 species of Allium. 



Another type may be observed in Alisma Plantago, L. var. 

 Americana R. et S. (Fig. 2). So far as concerns the structure of 

 the cotyledon, the seedling does not differ from that of Agave, 

 but if we examine the root we notice that this remains very short, 

 and that it bears a dense tuft of root-hairs at the base, where it 

 passes into the more or less distinct hypocotyl (H). We have, 

 thus, in this type of seedling an indication of a hypocotyl, and 

 among other plants that exhibit this manner of germinating, 

 and in which the seeds have no endosperm, maybe mentioned 

 Butomus, Typha, Triglochin, etc. ; in Juncus hujonius the seeds 

 contain endosperm, but the seedling shows, nevertheless, this 

 same structure, according to Mirbel (1810). 



We now proceed to a type of seedlings which is very frequent, 

 and much more so than those described above; in this, the third 

 type, the apex of the cot}dedon remains enclosed by the seed in 

 order to absorb the nutritive matters stored in the endosperm. 

 Moreover, the free portion of the cotyledon constitutes a sheath 

 of various length, at the bottom of which the plumule is located; 

 the primary root attains sometimes a considerable length 

 (Fig. 6), or it ceases to grow shortly after the germination has 

 taken place (Figs. 3 and 4). As shown in Figure 7, a hypocotyl 

 is developed, and this stem-portion is more distinct inthis type 

 of seedlings than in the former. In Ariscema iriphylhnn, Torr. 

 (Fig. 3), the apex of the cotyledon is readih' visible in longitudi- 

 nal section, and is surrounded by the endosperm; the'^plumule 

 with its first leaf is yet enclosed within the sheath, while the 

 primary root is free, and provided with hairs. A more advanced 

 stage may be seen in Fig. 4, where the leaf has broken through 

 the sheath, and where two secondary roots have developed. 

 During the first season the rhizome becomes formed by the growth 

 in thickness of the short primary axis (Fig. 5), and' attains the 

 shape of a round tuber bearing three secondary roots, which 

 rapidly increase in length, but without ramifying. In Smilax 

 rotundijolia, L. (Fig. 6), we notice a long primar}' root, which 

 stays active for at least one season, and the hvpocotyl (H) in 

 Fig. 7) is very distinct; otherwise the cotyledon shows the 

 same structure as in Ari.scema. The foliage of Smilax consists at 

 the seedling stage of several minute, scale-like leaves preceding 

 the green ones, of which mostly only one appears during the 

 first jj season. It is interesting to notice that a bud becomes 



