1914] CURRENT LITERATURE 443 
Reproduction in Scenedesmus.—Although Scenedesmus is a very familiar 
alga, the details of its reproduction had not been investigated, doubtless because 
the cells areso small. Smrru™ has studied the cell structure and reproduction in 
all of the three species. The cells are strictly uninucleate, contain a single 
pyrenoid, and have a cell wall consisting of two layers. When 4-celled colonies 
are formed, the steps are as follows: The first nuclear division is followed by 
a transverse cleavage of the cytoplasm, and nuclear division in the two resulting 
protoplasts is followed by cleavage furrows at right angles to the first furrow. 
de novo within each of the four cells, and cell walls appear. The young colony 
escapes through a longitudinal ‘rupture in the wall of the mother cell and 
assumes the characteristic arrangement by unrolling. In the formation of 
8-celled colonies, there are three nuclear divisions, the second and third being 
followed by cytoplasmic cleavages. The material for the study was grown in 
pure cultures. Sections were cut from 3-5 in thickness and stained in 
Flemming’s safranin-gentian violet-orange combination.—C. J. CHAMBERLAIN. 
The embryo of Gyrostachys.—The origin and development of the embryo 
sac of Gyrostachys, more commonly known as Spiranthes, is described for two 
species, S. gracilis and S. cernua, by Miss PAce,'s whose previous work allows 
her to speak with authority upon this subject. The embryo sac is very irregu- 
lar in its development, sometimes arising from 4 megaspores, sometimes from 
2, and sometimes from only one. At the fertilization stage the embryo sac 
may contain 4, 5, 6, or 8 nuclei, the 6-nucleate condition, resulting from a lack 
of one mitosis in the chalazal end of the sac, being the most frequent. The 
diploid number of chromosomes in S. gracilis is 30, and in S. cernua 60; con- 
sequently, the relation, in this respect, is similar to that between Oenothera 
Lamarckiana and O. gigas, and S. cernua might be called a tetraploid form. As 
is well known, S. cernua is a larger and more vigorous species, and the gigantism 
is evident also in the size of the ovary, the ovules, and the size of the cells. 
Miss PAcE suggests that the subject might be worth investigating experi- 
mentally.—CHarLes J. CHAMBERLAIN. 
Westphalian Calamariaceae.—A revision of the pea Calimsitincsus 
undertaken in conjunction with Kipston, impressed upon JONGMANS the frag- 
mentary condition of our knowledge of the Calamariceae of the Rheinish- 
Westphalian coal fields, and also the inadequacy of the descriptions and figures. 
Accordingly, with the cooperation of KukuK,™ he examined and described 
MITH, GILBERT M., The cell structure and pea formation in Scenedesmus. 
Acchis fiir Patina! 32:278-207. pls. 16, 17. 19 
*s Pace, Luba, Two species of Gyrostachys. Pa University Bull. 17:1-16. 
pl. I. 1914. 
6 Joncmans, W. J., and Kuxux, P., Die Calamariaceen des Rheinisch- 
Westfalischen Kohlenbeckens. Mededeelingen van’s Rikjs Herbarium. Leiden. 
no. 20. Text 8vo. pp. 89. Atlas 4to. pls. 22. 1913. 
