312 BOTANICAL GAZETTE [SEPTEMBER 
a still more complex process than the production of maltose from glucose, 
Meyer suggests * that similar relations may exist among other polysac- 
charides which are hydrolyzed by enzymes. Holding that the enzyme which 
digests starch has its origin in the plastids,3 he now thinks it probable that 
this enzyme acts like maltase. When a concentrated solution of sugar enters 
the stroma from the cytoplasm, amylose is formed, which on reaching a cer- 
tain concentration crystallizes out in the form of a starch grain; whileif 
sugar is wanting in the cell a relatively active inversion of amylose occurs, 
and a rapid solution of the starch grains. The suggestion is interesting and 
deserves careful testing.—C. R. B. 
Mr. W. H. Lang has published the second number“ of his series entitled 
“Studies in the development and morphology of cycadean sporangia,” deal 
ing with the ovule of Stangeria paradoxa. His results are as follows: two 
ovules are developed on each sporophyll; the archesporium consists of a mass 
of cells, one of which is selected, enlarges very much, and forms 2 row of 
three, the lowest cell of which organizes the megaspore ; at the time of pol- 
lination the sac is full of endosperm (but without archegonia), the pollen 
chamber is fully developed within the beak-like process of the nucellus, but 
the breaking down of nucellar tissue between the pollen chamber and te 
embryo-sac has not begun ; as in Cycas and Zamia, the sperms are large, 
Spirally twisted, and multiciliate, with the blepharoplast band evident ; dis- 
organization of endosperm tissue between the pollen-chamber and 
embryo-sac gives free access to the latter, and the sperms are discharged 
into the archegonial chamber of the nucellus, reaching the neck by sem 
ming.— J. M. C, 
‘ y be explained by double fertilization. H : | 
grain whose endosperm showed the characters of the pollinating os 
a hybrid embryo; and that every grain whose endosperm showed © 
acters of the embryo-sac parent had an embryo of pure race, and was 
fore self-fertilized. In a few words he puts it that double f 
corroborated by double hybridization.— J. M. C. 
™ Bot. Zeit. 577: 313. 1899. "3 Untersuch. iiber Starkekorne? 169. 
™ Annals of Botany 14: 281-306. pls. 17-78. 1900. 
‘SSur la fécondation hybride de l’endosperme chez le mais. 
Rev. gén- 4 ea 
Mique 12: 129-137, bl. 15. 1900. i 
ertilization 5 
Se ee 
