76 BOTANICAL GAZETTE [JANUARY 
might be established for each species. and it would be possible to estimate with 
some degree of accuracy the age of a tree from its diameter. From this stand- 
point Licnrer has investigated Quercus pedunculata, Castanea vulgaris, Sophora 
japonica, and Taxus baccata; and in a less complete way Sequoia gigantea, 
Cedrus Deodora, and Araucaria imbricata. There are three distinct periods in 
the rate of diameter increase: (1) the period of acceleration; (2) the period of 
decline; (3) the final period in which diameter increase is barely perceptible. 
Quercus begins its final period at about 140 years, when the radius is 57.9 °™5 
Castanea at 190 years, with a radius of 74.7°™; Taxus at 150 years, with a radius 
of 25.6°™. For each of the species investigated there is a table which gives the 
age in terms of the radius ——J. M. C 
Cytology of the Entomophthoraceae.—The preliminary announcement of 
RIDDLE’s results was noted in this journal.*9 The full paper has now appeared,”° 
Empusa Grylli and several species of Entomophthora were abate and 
the writer reaches conclusions somewhat different from those of OLIvE.** The 
nucleus is well developed, there being a chromatin nucleolus socoutded by 
chromatin granules. At division there is a well-developed mitosis, in which, 
however, the chromosomes are formed by a direct aggregation of chromatin 
granules without the formation of aspirem. ‘The spindle is intranuclear, bipolar, 
and without centrosomes. The conidia of Empusa are multinucleate and those 
of Entomophthora uninucleate. The zygospores of Entomophthora are formed 
by the fusion of multinucleate hyphal bodies. In Empusa the zygospores are 
formed by the budding out of a hyphal body. Cytological evidence favors the 
derivation of the Entomophthoraceae from a Mucor-like ancestry.—CHARLES J. 
CHAMBERLAIN. 
Parthenogenesis in Wikstroemia —WINKLER’S preliminary paper was reviewed 
in this journal,?? and now the completed results have been published.?s The 
present investigation shows that the embryo develops from the egg without 
fertilization, but whether the egg contains the sporophyte number of chromo- 
somes (52) or the gametophyte number (26) was not determined definitely. It 
is probable that the 88 viegh - he. sis i a number of chromosomes. oe 
proposes the phrase somatt for cases in which the em br Ops 
from an egg with the ce number of chromosomes, and seni pati 
ogenesis for cases in which the number has been reduced. He insists that an 
egg is an egg whether it has the reduced number of chromosomes or not. The 
19 Bor. GAZETTE 42:236. 1906. 
20 RIDDLE, Lincoxtn, W., On the cytology of the Entomophthoraceae. Proc. 
Amer. Acad. 42:177-197. pls. I-3. 1906. 
2t Bor. GAZETTE 41:2192~205, 229-259. 1906. 
22 Bot. GAZETTE 39:236. 1905. 
23 WINKLER, Hans, Ueber Parthenogenesis bei Wikstroemia indica. Ann. Jard. 
Buitenzorg II, 5:208-276. pls. 20-23. 1906. 
