76 BOTANICAL GAZETTE 
(yu 
Pollen grains of Picea.—Po.ttocxk4’ has described variations observed 
the pollen grain structures of Picea excelsa, chiefly in reference to the so-call 
ahaa cells. The usual number of these cells reported for the Abietine 
is two, but PoLtock finds the variation in Picea to range from one to thr 
ae one as.the number in the majority of cases. This is an interesting sitt 
tion, as these cells have been reported thus far for the conifers only among tt 
more easy Abietineae and Podocarpeae, and it shows that even here th 
are in a very fluctuating condition. The condition among the Arauca ne 
recently announced by THomson, is interpreted as representing a still grea 
multiplication of prothallial cells, an interpretation that is probably jus 
That among the conifers all stages in the elimination of this tissue are represen 
seems evident.—J. M.-C 
Sclerotinia on Forsythia.—OsTERWALDER*® has described a disease of s 
from. those date. causing a wilting of the twigs alone. Sclerotia are f 
the typical apothecia of Sclerotinia. Spores or mycelium grown the 
-produced the disease anew when placed on the floral parts. Although 
conidiophores occurred on some of the withered flowers, the author was 
to show that these were not connected with the Sclerotinia, thereby sue 
the view that Sclerotinia Libertiana has no conidial form.—H. Hasse 
A sterile Bryonia hybrid.—In studying the development of the sex org 
of a sterile hybrid of Bryonia alba and B. dioica, TIscHLER47 comes to the ¢ 
clusions that the absolute sterility has nothing to do with the tetrad form 
because the megaspore series shows the normal tetrads, and that while 
are irregularities i in the formation of pollen there are also cases in which no! 
bining culture methods and cytotogy—Cxar.Es J. CHAMBERLAIN 
Photosynthesis.—UsHER and PRIESTLEY have contributed strong suppor 
the theory of BAEYER that formaldehyde is the first product of photolysis of C' 
4s Pottocx, James B., Variations in the pollen ago of Picea excelsa. 
Nat. 40:253-286. pl. 1. 1906. 
4° OSTERWALDER, A., Die Sclerotienkrankheit bei den paren 
Pflanzenkr. 15:321-329. pl 5. 1905. : 
47 TISCHLER, G., Ueber die Entwicklung der Sesnanewaaine bei einem st 
Pimiefieressry Ber. Deutsch. Bot. Gesell. 24:83-06. pl. 7. 1906. 
