72 BOTANICAL GAZETTE [JULY 
Goebel, in regard to their physiological function, with the whole leaf-organ 
of the Hymenophyllaceae, and the present author suggests that the aphlebia 
of fossil ferns are to be similarly interpreted.— E. C. JEFFREY. 
THE CONDITIONS governing the germination of the spores of the brown 
rust of bromes (Puccinia dispersa Erikss.) have been closely studied by 
Ward. This rust is an excellent example of a parasite very closely restricted 
to certain species of hosts, yet forms were found bridging over widely sepa- 
rated sections of the genus. It is interesting to know that these uredospores 
retain their vitality for long periods, month-old spores germinating readily, 
and certain forms after sixty-one days. But the conditions governing the 
germination of uredospores are very uncertain, for there are internal factors, 
such as the age of the spore-bearing mycelium and degree of ripeness, 
beside the external factors of temperature, aeration, moisture, etc.—B, } 
Davis. 
PALLADINE AND KOMLEFF® have determined that the respiratory energy 
of cut etiolated leaves of Victa faba placed in solutions of cane sugar is 
greatest when the solution has a concentration of about 5 per cent. This 
fact seems not to depend upon sugar assimilation, for the latter increases 
with the concentration at least as far as a 20 per cent. solution, the highest 
concentration tested. But the respiratory energy is greatest when there is 
the largest amount of insoluble proteid substances present in the leaves, a 
condition attained in a 5 per cent. solution of cane sugar. When the leaves 
are transferred from one concentration to another respiration is augmented 
with decrease and diminished with increase of concentration. This supports 
the view that foods are not directly consumed in respiration BukTon E 
LIVINGSTON. 
“THE AECIDIUM as a device to restore vigor in the fungus”’ is the sub- 
et oe a short discussion by Professor Arthur,” who believes that the aecidium 
represents the original sexual stage of the 
rust. It appears that wheat infected from aecidial spores will produce teleuto- 
spores (black rust) much more quickly than if the infection be through uredo- 
spores, and it is well recognized that the black rust is more injurious to the 
wheat than the red rust. Hence the author regards the aecidiospore as more 
virile than the uredospore, since it produces a more vigorous and harmful 
parasite. The question, however, suggests itself whether this added virility 
has really any connection with the organ called the aecidium. It is possible 
Warb, H. M., Further observation on the brown rust of the bromes, Puccinia 
dispersa, and its adaptive parasitism. Ann. Mycol. 1: 132-151. 1903. 
6 PALLADINE, W., and KomLerFr, A., L’influence de la concentration des solutions 
sur )’énergie respiratoire et sur la transformation des substances dans les plantes. Rev. 
Gén. Bot. 14: 497-516. 1902. 
7 ARTHUR, J. C., The aecidium as a device to restore vigor to the fungus. Proc. 
Soc. Prom. Agric. Sci. 23: 1-4. La 
