208 BOTANICAL GAZETTE [September 



ledons forces the base of the embryo backward, so that both coleo- 

 rhiza and suspcnsor are crushed little by little to a flat, brown disk 

 (figs. 4, 5). Further elongation forces the base of the embryo 

 through the softer, micropylar portion of the seed coat ; figs. 6, 7, 8 

 show this and the two succeeding stages. In fig. 7 the base of the 

 cotyledon is curved downward, and the plumule is seen issuing from 

 between its opened edges; and it may be observed that this method 

 of development has thrown the first leaf out of alignment. The 

 edges close in again, and remain adhering the full length of the coty- 

 ledon (fig. 13). The tip is sometimes lobed (figs. 14, 15). 



The cotyledon always develops on the lower side of the embryo 

 as the seed lies during germination. In seedlings which were turned 

 after the cotyledon had begun to develop, the plumule has not suc- 

 ceeded after a year in emerging from underneath the cotyledonary 

 sheath with which it is hampered. 



Fig. 8 shows the appearance of the tardy root, which has made its 

 way through the brown cap formed from the remains of the disorgan- 

 ized coleorhiza and suspensor. When the root pierces the soil, the 

 starch is transferred to it from the endosperm, and the root thickens into 

 a tap root. By its further penetration into the soil, it often draws 

 the upper portion further down, imbedding the seed, and possibly 

 giving to the first series of lateral roots their initial upward slant. 

 The lateral roots almost always appear in threes, whether the root 

 be tetrarch or triarch. Fig. 9 represents a seedling toward the 

 close of this period of its activity. The extreme shortness of the 

 hypocotyl may be conjectured from the small distance between the 

 base of the cotyledon and the insertion of the first whorl of lateral 

 roots. The plumule is composed in this case of two brownish, hairy 

 scales, enclosing a foliage leaf with circinate vernation (fig. 10). 

 Each scale is terminated by a sharp, curved point. The number of 

 scale leaves varies in different seedlings; some have only one, and in 

 in some few observed the first organ was a perfect foliage leaf. The 

 base of both scale leaf and foliage leaf is furnished with broad, wing- 

 like expansions which enclose the next leaf. The petiole of the first 

 leaves reaches a length of 15-20°™ and bears one or two pairs of 

 pinnae inserted near the adaxial face. Between the two terminal 

 pinnae there is a tiny, sharp spine, which has its counterpart in the 



