344 BOTANICAL GAZETTE [april 



winter injury, failure of the seed crop, viability of the seed, impure and adulterated 

 seed, fodder, yellow trefoil, weeds. Among the fungous diseases discussed are: 

 Leaf spot, wilt, anthracnose, root-rot and damping off, downy mildew, Ascoclma 

 leaf-spot, Stagnospora leaf-spot, Cercospora leaf-spot, Alternaria disease ) 

 of seed, frost blisters on leaves, insect enemies, and root-knot; also, as diseases 

 of unknown cause, white spot, yellow top, pitting of the tap-root, and bundle 

 blackening in the tap-root.— F. L. Stevens. 



Barium and loco.— In a bulletin on loco weeds 21 Crawford says: "The 

 inorganic constituents, especially barium, are responsible for this action, at least 

 in plants collected at Hugo, Colo. Perhaps in other portions of the country other 

 poisonous principles may be found." Astragalus mollissimus and Aragallu 

 Lamberti were most fully studied, but other species of these genera, as well as 

 various other genera, have been reported as producing loco— Wm. Crocker. 



Protection against heating.— Wiesner holds that the distribution of green 

 tissues into small leaves or finely divided leaves is a mode of protection against 

 overheating by the sun, and adduces observations and experiments in suppo: 

 therefor." This protection is secured by the small size of the parts which expose 

 a relatively large surface for radiation and at the same time permit many ig 

 rays to pass them by. — C. R. B. 



Balanced solutions.— Osterhout continues his studies upon balanced u- 

 tions with plants, 2 * reporting that Na ions, by reducing the toxicity or K, . 

 Mg, and Ca ions, are an important, and in some marine algae an ^'^"^J 

 protection. He finds that there is no essential difference between plan 



animals in this respect.— Wm. Crocker. 



21 Crawford, A. C, Barium, a cause of the loco-weed disease. Bur. 

 U. S. Dept. Agric. Bull. 129. pp. 87. 1908. . sbeso ndere 



22 Wiesner, J., Versuche iiber die Warmeverhaltnisse kleiner ' D l " u S t fc B , 

 linear geformter, von der Sonne bestrahlter Pflanzenorgane. Ber. 



Gesells. 26a: 702-711. 1908. ' .^1, 



*3 Osterhout, W. J. V., Die Schutzwirkung des Natriums fur Pflanzen. 

 Bot. 46:121-136. 1908. 





