1908] CURRENT LITERATURE 79 
the present time. The paper includes a summary of many scattered contributions, 
and makes it clear that he had recognized, much earlier than Baur, the infectious 
character of certain forms of variegation. He contends, rightfully, that chlorosis 
is an inept term.—C. R. B. 
Sap rot of red gum.—Von ScHRENKS' describes diseases due to fungi which 
infect the sapwood of red gum (Liquidambar) when the logs lie in the forest while 
wet, and continue to spread, to the destruction of the lumber when cut. Poly- 
porus adustus, Polystictus hirsutus, and Poria subacida are the most frequent 
enemies, but there are a number of others. Sap rot may be prevented by hasten- 
ing the drying or by coating the ends of the logs as soon as cut with hot coal tar. 
Similar diseases injure the heartwood of red gum and also affect the swamp 
oak and maple. —C. R. B. 
Cytology of Microsphaera.—Sanps5? has shown that during all stages in the 
life-history of Microsphaera a central body is differentiated as a permanent 
nuclear structure, which serves as a point of attachment for the chromatin. 
It is always extranuclear, never intranuclear, as claimed by Marre and GUIL- 
LIERMOND. The delimitation of spores is accomplished by the astral rays 
persisting from the third mitosis in the ascus. The work in this respect 
Supports the conclusions of HARPER rather than those of FAULL.—CHARLES J. 
CHAMBERLAIN, 
Morphology of Cornus florida.—MorseEs3 has investigated Cornus florida 
and found the following facts: the male gametophyte passes the winter in the two- 
celled stage; no walls separate the nuclei of the linear megaspore tetrad; the 
embryo sac probably passes the winter in the eight-nucleate stage, which persists 
Until the last of May, when pollination occurs; the synergids are slender cones 
Projecting far into the micropyle; the endosperm tissue is formed first in the micro- 
pylar end of the sac, and by the middle of July completely fills the sac.—J. M. C. 
Fossil flora of Florissant —CockERELL*4 has enumerated the known flora of 
the Florissant shales (Miocene), including 106 genera, 45 of which occur in Colo- 
Taco today. Of the genera not occurring now in Colorado, 36 occur in our eastern 
and southern states, the conclusion being reached that a flora similar to that of the 
Carolinian region occupied the Rocky Mountains during the Miocene. About 
5° new species are described, including a Chara, a fungus, four ferns, and two 
8yMnosperms.—J. M. C. 
errr 
sia gps H., Sap rot and other diseases of the red gum. U. S. Dept. 
€., Bur. Pl. Ind., Bull. 114. pp. 32. pls. 8. 1907- : 
Tass M. C., Nuclear structure and spore formation in Microsphaera alni, 
~ Wis. Acad. Sci. 15:733-752. pl. 46. 1907. 
oe WILtiaM CiirForp, Contribution to the life history of Cornus florida. 
Agri 
*# COCKERELL, T. D. A., The fossil flora of Florissant, Colorado. Bull. Amer. 
» Hist. 24:71-110. pls. O-I0. 1908. 
