6i6 summAky of cueeent eeseaeches eelating to 



uppermost attaining a considerable length, while the lowermost 

 assumes a spherical form, both of these being remarkable for the 

 constant plurality of nuclei (Viciese, with the exception of Cicer 

 arietinum). 



3. It may be formed of a filament of cells of variable number 

 (Ononis). 



4. It may consist of a larger or smaller number of pairs of cells, 

 either superposed or in the same vertical plane (Lupinus), or in regular 

 alternation (Cicer arietinum). 



5. It may be composed of a greatly elongated cellular body, the 

 cells of which are either (1) quite distinct from the embryo (Medicago, 

 Trigonella, &c), or (2) not completely distinct (Oalega), or (3) much 

 confounded with it (Phaseolus, &c). 



6. The cellular body may be an ovoid or rounded mass, which 

 may differ as to the size, form, number, arrangement, and contents of 

 the cells, and as to their relation to the embryo (Cercis, Antliyllis, 

 Cytisus, &c). 



In the same genus of Leguminosae the type remains as a rule 

 constant, but differs within the tribe. In the Fumariaceaa we find, on 

 the contrary, Corydalis ochroleuca with a much- developed suspensor, 

 while 0. cava is entirely destitute of one. In the order Legu- 

 rninosae we find every type that occurs in all the other natural 

 orders. 



With regard to the formation of the embryo itself, after the primary 

 transverse segmentation which immediately follows fecundation, some- 

 times the lower. cell is itself the mother-cell of the embryo, sometimes 

 the mother-cell is not differentiated till after further divisions in the 

 suspensor ; the first case occurring in Lotus, Tetragonobolus, Trifolium, 

 Medicago, AntJiyllis, Phaseolus, &c, the second in Galega and the 

 Viciese. The first division in the embryo is not, as has often been 

 stated, invariably longitudinal ; in the Viciese it is transverse. 



The epidermis becomes differentiated on the surface of the embryo 

 before the appearance of the cotyledons. In embryos without sus- 

 pensor, as those of the Acacieae, the internal tissues are most strongly 

 differentiated ; in the Viciese, on the other hand, the cotyledons are 

 already considerably developed while the axis is still very short and 

 shows no internal differentiation. The size of the axis, as compared 

 to that of the cotyledons, varies greatly. In most of the Mimosese it 

 is very short, and manifests, long before it has attained any considerable 

 length, the lobes of its first compound leaves. In this tribe also the 

 synergidas sometimes develope into embryos, indicating that they may 

 probably partake of the nature of oospheres. 



The endosperm exists in the embryo-sac in two different states, 

 either of free nuclei on the cell- wall, or of a parenchymatous temporary 

 or permanent tissue ; the second always succeeding the first, except in 

 the true Vicieae. The mode of multiplication of the endosperm-cells 

 presents a close analogy to that of the suspensor ; fragmentation is a 

 phenomenon associated with age. The first cell-walls always make 

 their appearance at the summit of the embryo-sac, except in Lupinus. 

 The free nuclei always divide simultaneously, as also do those of the 



