148 THE JOURNAL OF BOTANY 
Lacoste.” In their a ii. 2, 438 (1904), ec ne & 
Graebner. say :—‘ Rhizom @ shortly creeping. Stems very 
ender. Rare ‘ May ui ily ‘ba confounded with J. bialtions 
x filiformis.’ Apparently this variety is new for Britain; 
Soathipist (v.-c. 59, S. Lanes.) specimens collected by Messrs. 
Adamson and Wheldon are, I think, the type, and much stronger. 
—Epwarp §. MarsHant. 
Arum macuLatum L.—May I direct attention to an interesting 
form of this plant seen in Surrey last year? Normally, the 
spadix is of a dull purplish hue, but in the form referred to this 
is of a clear yellow colour. In this my plant agrees with the var. 
Tetrelit Corb., described Bie Rouy (FI. de France, xiii. 
: : Bull. Soc. Lin 
Normandie, 5 sér. i. pp. 150-200. The variety (p. 196) 1 is dear’ 
only characterized by the colour of the stamens and spadix, which 
is stated to correspond with that of A. italicum; no reference is 
made by Corbiére to the veining of the leaves. —C. E. Brirron. 
REVIEWS. 
Transpiration and the Ascent of Sap. By Henry H. Dixon. 
Pp. vi.+216. London: Macmillan & Co., Ltd. 1914. 
Prices Bs. net. 
THE problem of the forces which bring about the rise of water 
in tall trees is one which has vexed botanists for very many years. 
A number of theories have been put forward to explain the 
phenomenon, but few of them have stood the test of critical 
examination in the light of modern plant physiology, based as it 
is on physics and chemistry. Of late years the dispute has been 
narrowed down to two acne opposed views. On the one hand, 
there is the view that the water rises in the stem owing to some 
io ene F of the ran ier of that organ of the nature of 
a pumping action. On the other hand, we have the purely 
physical view, “sebiols3 is eapidly gaining ground, that the stem is 
a mere passive agent in the process of water-rise, providing 
gies ed, in an international journal, Progressus Rei Botanica, a 
l account of the cohesion theory of the ascent of sap with a 
