e 
1908] CURRENT LITERATURE 77 
peptase, the other an ereptase. He hopes soon to arrive at a general conclusion 
as to the nature of ‘‘ vegetable trypsin,” which by his admirable researches so far 
seems resolvable into a peptase and an ereptase.—C. R. B. 
Structure of chloroplasts.—This has long been in doubt, the current doctrine 
being that the ordinary chloroplast consists of a stongy stroma in whose meshes 
the chlorophyll is held as a green fluid. Prresttey and Irvrnc show‘? that in 
the large chloroplasts of Chlorophytum elatum, Selaginella Kraussiana, and S. 
Martensii the chlorophyll is restricted to a peripheral zone, probably less than 1 
thick, where it is held in the meshes of a spongy stroma. This agrees with the 
arrangement theoretically best according to TrmmertazeErF. The authors also 
confirm the neglected observations of NAGELI and TimerazerFr on the splitting 
of the chloroplasts in solutions of low osmotic pressure.—C. R. B. 
Morphology of wheat.—ArrHur H. Dupiry,‘+ in a presidential address 
before the Liverpool Microscopical Society, presented an account of floral devel- 
opment, sporogenesis, and embryogeny in wheat. A summary of his results is as - 
follows: the archesporium of the microsporangium is a single row of cells, two or 
three divisions occurring before the mother-cell stage is reached; the arche- 
sporial cell of the megasporangium does not cut off a parietal cell, but produces 
directly the linear tetrad, the reduction number of chromosomes being eight; 
. large development of antipodal tissue occurs; and the embryo is said to be 
derived from the “apical cell only”’ of the proembryo.—J. M. C. 
Scion and stock.—GurtcNnarp has made another attempt to settle the question 
whether compounds peculiar to either scion or stock are able to migrate past the 
point of grafting.*5 When a plant which contains an HCN-glucoside is grafted 
ona Plant which contains none, or conversely (GUINARD used Phaseolus lunatus, 
Photinia serrulata, and five species of Cotoneaster), there is no transfer of this 
glucoside in either direction. This adds one more bit to the negative evidence 
eas accumulating against the uncertain positive claims of such migration. The 
Paper contains a good history of the question.—C. R. B. 
Tolerance for salts.—Continuing their work on the relation between alkali 
Bey and vegetation, KrarNey and Harter, testing pure solutions of various 
Xa. find¢* that different species and even different varieties of the same species 
lier considerably in resistance to the action of magnesium and sodium salts. 
Sar ee 
oa ed RIESTLEY, J. H., and Irvinc, ANNIE A., The structure of the chloroplast 
sidered in relation to its function. Annals of Botany 21:407-413- figs. 2. 1907- 
Liv, ie Duptey, ARTHUR H., Floral development and embryogeny in wheat. Report 
*rpool Micros. Soc. 1908 1-19. pls. I, 2. 
eae Guicnarp, L., Recherches physiologiques sur la greffe des plants & acide 
Atha Ann. Sci. Nat. Bot. IX. 6:261-305. jigs. 9. 1907. 
erie Kearney, T. H., and Harrer, L. L., The comparative tolerance of various 
: 's for the salts common in alkali soils. U.S. Dept. Agric., Bur. Pl. Ind., Bull. 
13. pp. 22. 1907. 
