246 BOTANICAL GAZETTE [MARCH 
state of the fungus was not observed by von LAGERHEIM,® or by MAGNus,** 
and has never been found by the reviewer. Even at a very early stage a 
definite mycelium appears to be present in the host plant, the hyphae of which 
are bounded by a thin wall. The ends of these hyphae form small swellings. 
or vesicles which are active in dissolving the walls of the host cells. The 
method of branching of the hyphae and the development of the resting spore 
e H GN a N 
and for others which they Snide closely allied to it. It is hoped to publish 
shortly a full account of this investigation and of a number of infection experi- 
ments undertaken in connection with several outbreaks of the disease in this 
country.—JAMeEs Line, Botany School, Cambridge, Engla 
Radio-active material. BLACKMAN gives an extremely clear statement 
of the possible significance of radio-activity in normal physiological processes. 
He discusses mainly the work of the Dutch investigator H. ZWAARDEMAKER 
(Jour. Physiol. 53:273-289. 1920), in which he found that various radio-active 
materials would maintain or induce heartbeat in a potassium-free Ringer 
solution. This is taken as evidence that the effectiveness of potassium salts on 
heartbeat is due to the radio-activity of potassium, for in equal radio-active 
concentration uranium and radium were equally effective with potassium. 
Potassium gives only #-radiations. Elements that emit only a-radiations 
were also effective in inducing and effecting ‘cheat 
“The mode of action of these corpuscular radiations is not clear. The 
charged particles as they shoot along will act by induction, detaching every- 
where electrons from these atoms; they also transfer kinetic energy, and when 
they come to rest on, say, some colloidal complex of the cell, they will transfer 
their electric charge and so may set free some ion absorbed on the surface. 
Whatever the nature of the action, ZWAARDEMAKER concludes that radio- 
activity is a mighty biological factor capable of restoring a lost function.” 
BLACKMAN believes that this may explain, in part, the function of potassium 
in the plant—Wwa. CROcKER. 
Subalpine lake shore vegetation—To his already extensive studies of 
Colorado mountain vegetation, RAMALEY% has recently added a report based 
upon a ten years’ study of numerous subalpine lakes located at altitudes of 
10,000-11,300 ft. in the Rocky Mountains of Colorado. Data are presented 
3x°von LAGERHEIM, G., Bihang K. Svenska Vet. Akad. Hand. 24: no. 4. 1898. 
3« Macnvs, P., Ann. Botany 11:87. 1897; Ber. Deutsch. Bot. Gesells. 20: 291-296. 
32 SCHROETER, J., Bot. Centralbl. 11: 219-221. 1882. 
33 BLACKMAN, V. H., Radio-activity and normal physiological function. Ann. 
Botany 34: 299-302. 1920 
34 RAMALEY, F., Subalpine lake sh getation i rth central Colorado. Amer. 
Jour. Bot. 7:57-74. figs. 6. 1920. 
