56 Biologie. — Cytologie und Befruchtung. 



mata, Trichome und Zellinhaltsstoffe (Stärkeschicht, Calcium- 

 oxalat und Crystalle unbekannter Zusammensetzung bei 

 Thallctnim slmplex und galioides und der Gattung Ceratoce- 

 phaliis) sich erstreckt. Bemerkenswerth erscheint, dass die 

 bekannte, den Glanz der Blumenblätter bedingende Stärke- 

 schicht auch bei Arten mit weniger glänzenden Fetalen auftritt 

 und in beiden Fällen beim Verblühen nicht verschwindet. Mor- 

 phologisch sind nach Verf. die Nectarien der Gattungen Myo- 

 siu'iis , Tiolliiis, Eranthis , Helleborus, Isopyniin, N ige IIa, 

 Delphinium und Aconitum als Kronenblätter aufzufassen. 



Büsgen. 



Frye, T. C. and E. B. Blodgett, A contribution to the life 

 history of Apocynum androsaemifoliiim. (Bot. Gaz. XL. 

 July 1905. p. 49—53.) 



The structure of the flower is very similar to that of 

 Asclepias previously studied by Frye. The tapetum is exceptional 

 in being derived from the homologue of the primary sporo- 

 genous layer; the ovule shows no primary parietal cell; and 

 the nucellus consists of a single layer of cells. 



M. A. Chrysler. 



Johnson, D. S., Seed development in the Piperales and 

 its bearing on the relationship of theorder. (Johns 

 Hopkins Univ. Circ. CLXXVIII. May 1905. p. 28—31.) 



The development of the megaspore and gametophyte is 

 found to vary too greatly within the order to be a satisfactory 

 index of relationship. The author considers certain features of 

 the development of the seed to be more reliable criteria, and 

 concludes that the Piperales are not very primitive Angiosperms 

 and are probably related to other Orders with perisperm- 

 containing-seeds. M. A. Chrysler. 



Lewis, L F., Notes on the development of Phytolacca 

 decandra L. (fohns Hopkins Univ. Circ. CLVIll. May 1905. 

 p. 34—42.) 



Development of the sporangia and spores is regulär, though 

 it may be noted that the tapetal cells contain from four to six 

 nuclei. The campylotropous ovule contains a crook-shaped 

 endpsperm, and a mass of perisperm located on the inner side 

 of vYie crook. In the endosperm the nuclei lie free at first but 

 cell formation proceeds from the micropylar end, leaving only 

 a mass of protoplasm at the chalazal end. In its early stages 

 the embryo is spherical and undifferentiated; at a later stage 

 the cotyledons displace most of the endosperm, which has in 

 its turn dissolved away the nucellus about the whole periphery 

 of the seed. M. A. Chrysler. 



