THE EMBRYO 



203 



egg is transverse, but this may be followed either by longi- 

 tudinal or transverse divisions, in the former case generally re- 

 sulting in a massive and often globular proembryo, in the latter 

 resulting in an extraordinarily long and conspicuous filamen- 

 tous proembryo. In almost every case the suspensor-cells are 

 more or less swollen and bladdery and surcharged with nutritive 

 material, forming a conspicuous nutritive tissue for the embryo. 

 The two types of proembryo may be illustrated as follows : 



As illustrations of the massive proembryo, in which the sus- 

 pensor and embryo are gradually differentiated, but are never 

 very distinct externally except by a constriction between them, 

 may be cited species of Acacia and Mimosa] Cercis siliquas- 

 trum, in which the oblong proembryonic mass broadens at each 

 end to form the embryo and suspensor ; Caesalpinia mimosoides, 

 in which the embryo becomes distinct rather early as the region 

 of more actively dividing cells; Cytisus Laburnum, in which 

 the suspensor becomes a great mass of loose rounded cells re- 

 sembling a globular cluster of berries; Anthyllis tetrapliylla, 

 in which the suspensor is like that of Cytisus, but the clustered 



FIG. 96. Embryos of Leguminosae. A, Cercis siliquastrum, with suspensor and embryo 

 developing about equally ; x 270 ; B-E, Spartlum junceum : e, embryo ; , suspen- 

 sor ; x 300. After 



cells are much fewer in number ; Spartium junceum and Trifo- 

 lium resupinatum, in which the massive proembryo seems to 

 constrict as in Cercis, but the suspensor as the cotyledon stage 

 approaches is smaller than the embryo; Tetragonolobus pur- 

 pur ens, in which the larger part of the massive proembryo be- 

 comes the suspensor; Hedysarum coronarium and Arachis hypo- 



