AGRICULTURAL BOTANY. 335 



the transpiring power of floral parts, the rehition of transpiration to wilting, 

 and transpiring power as an index of drought resistance. 



The results as detailed are said to show the suitability of the method for 

 use in the study of several aspects of ecological behavior. It may offer a simple 

 and adequate means of classifying plant forms in a scale of xerophytism or of 

 mesophytism, based upon water requirement so far as this depends upon 

 foliar transpiring power, which in turn must take into account the full diurnal 

 course of transpiration, or at least nximerous daily determinations. 



Age, position, and structure of the leaves may influence transpiring power, 

 as may also the humidity of the surrounding media. 



A bibliography is appended. 



The anthocyan pigments, A. E. Everest (Set. Proff. Twentieth Cent., 9 

 (1915), No. S6, pp. 597-612, figs. 5). — This is a review of work bearing upon the 

 nature and composition of the red, purple, and blue flower pigments. 



Our present knowledge of the chemistry of the Mendelian factors for 

 flower color, Muriel Wheldale (Jour. Genetics, If (1914), No. 2, pp. 109-129, 

 pi. 1; abs. in Internat. Inst. Agr. [Romel, Mo. Bui. Agr. Intel, and Plant Dis- 

 eases, 6 {1915), No. S, pp. Jf04, 405). — In the present paper an attempt has been 

 made to state, from the evidence available, just what is known of the chemical 

 mechanism underlying the Mendelian factors for flower color, and the views 

 of several investigators are discussed. 



It is stated that there are varieties of Antirrhinum majtis, ivory, yellow, 

 and white, which do not form anthocyanin, ivory being dominant to yellow and 

 containing a factor which is absent from yellow. It is claimed that the pig- 

 ments in the ivory and yellow varieties are flavones, ivory containing a pale 

 yellow flavone, apigenin, and yellow containing in addition a deeper yellow 

 flavone, luteolin, the formation of which is presumably inhibited by the factor 

 which is present in the ivory. The white variety contains no flavone. When 

 the yellow or ivory is crossed with a white of suitable composition, the Fi de- 

 scendants contain anthocyanin, which therefore appears to have been formed 

 from a flavone by the action of some factor contained in the white. It has 

 been suggested that anthocyanin is either an oxidation or a condensation prod- 

 uct of a flavone, or both. 



Two anthocyanins have been isolated from Antirrhinum, red and magenta, 

 the latter containing a factor which is absent from the red. Both red and 

 magenta contain more oxygen than do the flavones, and magenta contains more 

 than red. 



A bibliography is appended. 



Our present knowledge of the chemistry of the Mendelian factors for 

 flower color, II, Muriel Wheldale (Jour. Genetics, 4 (1915), No. 4, pp. S69- 

 576). — Since the appearance of the above paper, further work on this subject 

 by several authors has appeared, and the present paper is concerned with the 

 bearing of the results announced on the genetics of flower color. 



The origin of dwarf plants as shown in a sport of Hibiscus oculiroseus, A. 

 B. Stout (Bui. Torrey Bot. Club, 42 (1915), No. 8, pp. 429-450, pis. 2).— An 

 account is given of studies carried out with the progeny of a single dwarf 

 plant of H. oculiroseus, which is said to have appeared in a pedigreed culture 

 as a sporadic variation, differing from the robust form in having short intei'- 

 nodes, dwarf stature, and smaller leaves (many of which were crinkled), also 

 in the development of lateral branches near the base. 



Plants intermediate in form appear in the progeny of this individual, pos- 

 sessing one or more characters of the dwarf type in some degree of develop- 

 ment, but no dwarf was found among the 103 descendants of its 4 sister plants. 



