1914] GATES—XEROPHILY 487 
while the extreme winter of 1911-1912 killed the parts of the ever- 
green ericads which projected above the snow; and in view of the 
fact that the evergreen habit is hereditary, that the position of the 
leaves in winter is different from that in summer, and that the 
transpiration is decidedly less than that of deciduous shrubs and 
of herbaceous plants in summer but greater in winter, the xero- 
morphy of these plants is real xerophyty, occasioned fundamentally 
by the necessity of protection when exposed to winter conditions 
and used advantageously by these plants during the summer. 
UNIVERSITY OF — 
ANN ARB 
LITERATURE CITED 
1. Bascocx, S$. M., Metabolic water: Its production and réle in vital phe- 
nomena. Univ. of Wis. Agric. Exper. Station, Research Bull. 22. 1912. 
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New York. 1906. 
- BurcersteIn, A., Die Transpiration der Pflanzen. Jena. 1904. (Con- 
tains a very extended bibliography of the subject.) 
Cannon, W. A., The root habits of desert plants. Carnegie Institution 
of Washington, Publ. 131. rort. 
- COPELAND, E. B., The rise of the transpiration stream: an historical and 
critical discussion. Bor. Gaz. 34:161-193, 260-283. 1902. (Contains 
a very complete bibliography up to 1902. 
- CovitLe, F. V., Experiments in blueberry culture. U.S. Dept. Agric., 
Bur. Pl. Industry, Bull. 193. 1910 
, The use of acid soil for raising seedlings of the mayflower, Epigaea 
repens. Science N.S. 33:711-712. I911 
- Cowxes, H. C., The causes of vegetative cycles. Bor. Gaz. 51:161-183. 
IQII, 
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Gaz. 46:130-143. 1908. 
, Bog toxins and their effects upon soils. Bor. Gaz. 47:389-405. 
= 
w 
> 
uw 
n 
oo 
‘© 
1909. 
11. ————, Physiologically ae habitats and drought resistance in plants. 
Bor. Gaz. 49 325-330. 
, The relation of Ohio ie estat to the chemical nature of peat 
soils. Bull. Torr. Bot. Club 39:53-62. 19 
13. Darwin, F., On a eacmianion metho cold to the movements of 
stomata. Ror. GAZ. 37:81-105. 
14. Davis, C. A., Peat. Report te Sunny Michigan. 1906 and 1907. 
15. Der, E. MaRios, Transpiration in succulent plants. Ann. Botany 26: 
409-442. 19 
