238 BOTANICAL GAZETTE [MARCH 
sity has published an account of observations and experiments regarding 
five serious diseases of the Irish potato that are known to occur in Florida: 
late blight, caused by Phytophthora infestans; early blight, caused by Alternaria 
solani; scab, caused by Oospora scabies; rhizoctonia blight, caused by a species 
of etclanctunig and bacterial blight, caused by Bacillus solanacearum. A brief 
discussion of the nature and effects of each disease is accompanied by statements 
as to the proper methods of control to be employed in each case.—E. MEAD 
WILCox. 
From A consideration of the various causes assigned by different authors as 
inducing flower-formation, Lozw4+ believes that such causes have one common 
physiological factor, namely, an increased concentration of sugar. He advances 
the theory that flower-formation is a phenomenon of irritability; that a certain 
concentration of sugar in the plant stimulates the embryonic substance to differ- 
entiate male and female nuclei. nian Si the evidence offered is very 
limited and not at all conclusive-—RAYMOND ND. 
NATHANSOHN’S last work on permeability of the plasmatic membranes of 
plants,45 which was reviewed in these pages some time since,*® includes in SS ~ 
cussion the results of a large series of experiments with the tissue of Dahlia tu 
The paper which embodied the details of this work, though actually ere 
before the one already reviewed, has but recently come to hand.47_ T hose inter- 
ested in this subject will need to read the two papers together —B. E. Livinc- 
STON. 
THE FIRST NUMBER of the second series of KaRSTEN and ScHENck’s*® Vege 
tationsbilder comes from the hand of Ute, the well-known student of the 
South American tropics. The number is devoted to the illustration of some 
characteristic epiphytes of the Amazon district, and the Standard of the preceding 
numbers is fully maintained. Among the epiphytes figured are Nidularium, 
Platycerium, Polypodium, Cereus, and Anthurium.—H. C. CowLes. 
THE INFLUENCE of weak aqueous solutions of ether upon the growth of 
Spirogyra has been studied by Grrasstmmow.49 In these cultures many of the 
UME, H. Haroxp, Potato Diseases. Bull. Florida Exp. Stat. 75 77-199 
pl. I-4 and frontispiece. 1904. 
44 Loew, Oskar, Zur Theorie der bliitenbildenden Stoffe. Flora gg: 124-128 
1905. 
45 NATHANSOHN, A., Weitere ce at iiber die Regulation der sic 
nahme. Jahrb. Wiss. B Bot. 40: 
46 Bot. GAZETTE = 477- 1904. al 
47 NATHANSOHN, A., Ueber die Regulation der Aufnahme anorganischer — 
durch die Knollen von gett aa ahrb. Wiss. Bot. 39: 607-644. 1904- 
48 Karsten, G., und ScHenck, H., Vegetationsbilder. Zweite Reihe, oe 
E. Ure, Die Epiphyten des date Tafel 1-6. Jena: Gustav . 
1904. Single parts M 4; to subscribers M 2.50. s 
49 GERAssimow, J. J., Aetherkulturen von Spirogyra. Flora on 
