680 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Haptera.* — E. Warming proposes this term for organs of various 

 morphological value which have for their function the attaching or 

 fixing of the part from which they spring ; for example, the apparatus 

 for attachment of young (Edogonium filaments, ordinary rhizoids, root- 

 hairs, the attachment-organs of the larger Fucaceae, the adhesive 

 tissue of Cuscuia and Cassytha, the attachment-disks of many climbing 

 plants, such as Ampelopsis, Trichosanthes, Glaziovia, &c. To this 

 category belong the peculiar organs of the Podostemacese, which the 

 author had previously described as metamorphosed roots, but which, 

 from an examination of the genus Castehiavia, he now regards as 

 emergences attached to the root. 



Chlorophyll and Chlorophyllan.f — The following are the main 

 results of a fresh examination of the nature and properties of chloro- 

 phyll by A. Tschirch : — 



Since the chlorophyll-pigment, probably dissolved in an essential 

 oil, permeates the protoj)lasmic matrix of the chlorophyll-bodies, and 

 presents the greatest possible surface for the assimilation of carbonic 

 acid, it is probable that it plays not merely a physical, but also a 

 chemical part in the process of assimilation. Chlorophyllan (the 

 hypochloriu of Pringsheim) is the first j)roduct of oxidation of the 

 pigment. It is formed in acid solutions, and by the action of all 

 acids, mineral as well as organic, even carbonic acid. Vegetable 

 acids are always present in the cell-sap, and hence chlorophyllan is 

 always formed in time in alcoholic solutions of chlorophyll. It can 

 be obtained by three methods: — (1) by evaporating an alcoholic 

 solution of chlorophyll, washing the residue with water, dissolving in 

 ether, and allowing the chlorophyllan to crystallize out ; (2) by 

 evaporating a concentrated alcoholic solution of chlorophyll to half 

 its volume, when impure chlorophyllan will crystallize out on cooling, 

 which can be purified by recrystallizing ; (3) by extracting leaves 

 with hot glacial acetic acid, evaporating, washing with water, dis- 

 solving in alcohol, and allowing to crystallize. 



Chlorophyllan is insoluble in water, soluble in alcohol, very 

 soluble in ether and benzin. The solutions are brownish green. It 

 crystallizes out of impure solutions in long whiplike or corkscrew- 

 like threads, or bone-shaped or pear-shaped masses, out of pure 

 solutions in a spherical mass of needles collected round a centre ; on 

 very slow crystallization in rectangular plates belonging to the quad- 

 ratic system. In transmitted light it is a dark olive-brown colour ; 

 in reflected light nearly black. In diffused daylight it exhibits no 

 polarization phenomena, but in direct sunlight these are very beau- 

 tiful. The spectrum of its solutions shows three lines, and continuous 

 absorption of A. = 46. Specially characteristic is line IV. h of 

 A = 51*3 — 44 '3, peculiar to the chlorophyllan-group. Lines II. 

 and IV. are considerably darker and broader than in solutions of pure 

 chlorophyll. Fluorescence of homogeneous red of wave-lengths from 

 64 to 68 hundred-thousandths of a millimetre. 



* Bot. Ztg., xli. (1883) pp. 193-200. 



+ Ber. Deutsch. Bot. Gesellscli., i. (1883) pp. 137-40, 171-81, 202-7. Cf. 

 this Journal, i. (1881) p. 479 ; ii. (1882) pp. 528, 817. 



