Morphologie, Teratologie, Befruchtung, Cytologie. 39 



5. gyacilis and 5. cernna. The embryosac is very irregulär in its 

 development, sometimes developing from four megaspores, some- 

 times from two, and sometimes from onl}' one. The embryosac, at 

 the fertilization stage, may contain four, five, six, or eight nuclei, 

 the six nucleate sac, resulting from the lack of one mitosis in the 

 chalazal end, being the most frequent. 



The diploid number of chromosomes in S. graciUs is 30, and in 

 5. cey}ma, 60; consequently, the relation in this respect, is similar 

 to that between Oenotheva Laniarckiana and O. gigas, and 5. cernua 

 might be called a tetraploid form. As is well known, 5. cernua is a 

 larger and more vigorous species than 5. gracilis, and the gigantism 

 is evident also in the larger size of the ovary, the ovules, and in 

 the size of the cells. Miss Pace suggests that the subject might be 

 worth investigating experimentally. 



Charles J. Chamberlain (Chicago). 



Petry, L. C, A protocorm of Ophioglossuni. (Bot. Gaz. LV, 

 p. 155-166. Feb. 1913.) 



A specimen from Mexico has a nearly spherical form, with a 

 deep depression in the centre of the top. A reconstruction of the 

 vascular sj'-stem shows that the central C3^1inder is everted , so that 

 the oldest of the seven leaves is attached to the top of the depres- 

 sion. The vascular structure and the apical cell are described and 

 figured. M. A. Chrysler. 



Saxton, W. T., Contributions to the Life-history of Tetra- 

 clinis articulata, Masters, v^^ith some Notes on the Ph5'"lo- 

 geny of the Cupresso'ideae and Callitroideae. (Ann. Bot. XXVII. 

 p. 577—605. 3 pl. 9 textfig. 1913.) 



Tetraclinis articulata is the Gum Sandarach tree of Morocco 

 and Algeria, which has generally been referred to under the 

 name of Callitris quadrivalvis. The material used in the present 

 investigation was obtained from a tree growing in the grounds of 

 the South African Museum, Cape Town. The tollowing are the 

 more important of the results obtained by the author: 



In the microsporogenesis no fusion of two spiremes occurs 

 at about the time of synapsis. The mother-cell does not become 

 partitioned during the development of the microspores. The mature 

 pollengrain is uninucleate. The ovule closely resembles that of 

 other Cupresso'ideae, and has a Single functional megaspore mother-cell, 

 surrounded by tapetal tissue. The possibility is suggested that all 

 the Cupvessoideae conform to this type errors of Interpretation ac- 

 counting for descriptions of a quite different structure in two 

 genera. Lateral archegonia occasionally occur. In fertilization the 

 male nucleus is about-one-quarter of the size of the female. Com- 

 plete fusion of the male and female nuclei occurs while both are 

 in the resting stage. In the prophases of the first sporophyte division 

 a segregation of the chromosomes into two groups occurs (presu- 

 mably male and female). This is regarded as important evidence 

 of the continued individuality of male and female chromosomes. 

 Wall-formation in the proembryo apparently occurs in the transition 

 from the four-nucleate to the eight-nucleate condition. More than 

 one tier of cells takes part in the formation of thesuspensor. Three, 

 four, and five cotyledons were found respectivel}'' in the three mature 



