26 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



were noted between this species, however, and the gen- 

 erally accepted account of the early divisions in the mono- 

 cotlydenous embryo, which tend to verify the recent account 

 given by Schaffner for Alis^na, and to indicate the necessity 

 for a further revision of the older work on the embryogeny 

 of other Angiosperms. 



After fertilization is effected, the ^^g becomes invested 

 with a cellulose membrane and elongates considerably before 

 dividing. It is in contact, usually, with the wall of the 

 embryo-sac, except at the apex. The nucleus at this stage 

 (fig. 60) is large and very conspicuous, with large nucleolus 

 and abundant chromatin. The cytoplasm is granular, 

 especially at the apex, where the nucleus is placed. At this 

 stage one of the synergidae is still unchanged, but the other 

 can no longer be made out, nor is the pollen-tube any longer 

 visible. 



The first division wall, as usual, is transverse, dividing the 

 ^gg into a basal, or " suspensor," and a terminal, or " em- 

 bryo," cell. The basal cell, which is apphed to the wall of 

 the embryo-sac, undergoes no further division, and all the 

 subsequent growth of the embryo is due entirely to the 

 divisions of the terminal cell. Hanstein (Sachs' Text-book 

 of Botany, 1882, p. 589) states that in Alisma the terminal 

 cell only produces the cotyledon, while the basal, or sus- 

 pensor cell, undergoes further divisions by transverse walls, 

 resulting in the formation of other parts of the embryo. 

 Famintzin, to judge from the review of his paper in Just's 

 Jahresbericht (Jahrg., VII, heft i, p. 90), agrees in the 

 main with Hanstein. According to his account, the first 

 three divisions are transverse and occur in regular basipetal 

 order, and these result at once in the establishment of the 

 initials for cotyledon, stem, and root. The early stages of 

 the embryo of Alisma have been investigated recently by 

 Schaffner (1896, pp. 129, 130), and he states that the con- 

 clusions of Hanstein and Famintzin are either incorrect, or 

 that there is remarkable variation in Alisma. According to 

 his account, the basal cell undergoes no division, agreeing 

 with my observations in Naias, and the next divisions are 



