1919] CURRENT LITERATURE loi 



some indication that other inorganic compounds may stimulate root growth in 

 cuttings. The author's work gives further strong evidence that callus and 

 root growth is independent of the rest period and that only the buds assume the 

 resting condition. Immature twigs were caused to absorb cane sugar which 

 increased root development. Mature twigs, however, were but slightly bene- 

 fited. When the base of cuttings w-ere placed in sugar solution for a short time, 

 the terminal bud of the twig failed to develop in a normal manner and the 

 lower buds formed shoots instead. The author believes that many of the 

 practices commonly followed by greenhouse and nursery men in the propagation 

 of plants by cuttings are explainable on the basis of better aeration. The 

 discussions of the literature are comprehensive and critical. — Charles 0. 

 Appleman. 



Vegetation of Newfoundland. — In contrasting the divergent floras of 

 different parts of Newfoundland, Fernald'^ bases his explanation of their 

 differences upon the hypothesis that "the presence or absence of varying 

 degrees of available lime or of other bases in the soil is more fundamental in 

 determining plant distribution than are even considerable differences of temper- 

 ature and humidity." 



The calcareous and at the same time the most fertile portion of the island is 

 along the west shore, where the ordinary observer would be surprised to find the 

 indigenous flora of the warmest and most fertile region of the island composed 

 very largely of species of high northern distribution, such as Juncus triglumis, 

 Saxifraga oppositifolia, S. aizoides, S. caespitosa, Salix vestita, Dryas integri- 

 folia, and Lesquerella arctica. These Fernald explains as being from the cal- 

 careous habitats of the arctic archipelago and the Canadian Rockies, the Ume 

 being hostile to the plants of the siliceous adjacent mainland. The eastern 

 part of the island, the central tundra district, and the southwest corner, in 

 spite of the fact that they are cold, bleak, and barren, are populated mainly 

 by plants of the southern Atlantic coast region, with an addition of some like 

 Calliina vulgaris and Pedicidaris sylvatica from the acid soils of western Europe. 



Maps of the distribution of a dozen species give graphic demonstration of 

 the remarkable distribution of some of the more important plants and serve 

 to make the evidence in the support of his hypothesis the more convincing. — 

 Geo. D. Fuller. 



Physiological role of glucosides in plants. — Continuing his investigations 

 on the physiological role of glucosides in plants, Combes'^ has made the inter- 

 esting discovery that a given glucoside is not toxic to a plant which naturaUy 



•-t Fernald, M. L., The contrast in the floras of eastern and western Newfound- 

 land. Amer. Jour. Bot. 5:237-247. pis. j. 1918. 



's Combes, Raoul, Recherches biochemiques experimentales sur le role physio- 

 logique des glucosides ches les vegetaux. Rev. Gen. Botanique 30:226-237, 245-257. 

 1918. 



