30 THE JOURNAL OF INDIAN BOTANY. 



rogenous initial to the mature pollen grain, and may involve only the 

 sporogenous tissue and its products, or the entire anther ; (b) in the ovary 

 at any stage from the functioning megaspore to the maturing fruit, and 

 may involve only the embryo-sac, or both embryo-sac and ovule, or the 

 entire ovary; (c) in entire inflorescences. The degeneration is accompanied 

 by, and probably caused by, the formation of a definite abscission layer 

 across the peduncle, whereby the floral organs are cut off from nutriment, 

 and is so common that functionally perfect flowers are rare. As a result 

 of such degenerations four types of mature flowers are produced (a) physio- 

 logically staminate (the ovary being functionless) in which the pollen may 

 or may not be functional ; (b) physiologically ovulate, the stamens having 

 been completely eliminated by degeneration ; (c) bisporangiate, having both 

 stamens and ovary functional (very rare); (d) completely sterile, having 

 functionless ovary and stamens completely eliminated. The author dis- 

 cusses shortly the bearing of these facts on the origin of dicliny, which he is 

 inclined to consider may be due in other species also to gradual degenera- 

 tions, and not as Strasburgher supposed to excessive mutation, nor to an 

 absence of one sex in the seed, as suggested by Hoffmann, nor to hybridisa- 

 tion as Jeffrey believed. P. F. F. 



Seedling Structure. 



Compton, R. H. An investigation of the Seeding Structure in the 

 Leguminosese. Jour. Linn. Soc. {Botany XLI No. 279, pp. 1 — 129 

 {June 1919.) 



A description with illustrative figures is given of the distribution of the 

 xylem and phloem in seedings of species taken from all sections of the 

 order. It would be impossible in a brief note such as this to summarise 

 or even indicate the facts and ideas which the author gives; but it is 

 clear that there is considerable variation in the amount and arrangement 

 of the xylem elements in the root from a solid tetrarc core, to a ring 

 of eight separate Y-shaped masses (as seen in section.) Those interested 

 would do well to read the paper. But two conclusions may be given 

 here— one that the size of the seeds is correlated with the habit of the 

 plant, trees having much heavier seeds than herbs or shrubs ; the other 

 that as with Angiosperues in general the tree habit is primitive, the her- 

 baceous derived. As to whether the epigeal or the hypogeal mode of 

 germination is the more primitive it is impossible to say. Both occur 

 sometimes in the same genus, and the change from one to the other has 

 probably occurred repeatedly in the evolution of the order. P. F. F. 



Pollination Mechanisms. 



Wyley, R. B. The Pollination of Vallisneria spiralis. Bot. Gaz. 

 I XIII, pp. 135—145. 



The mechanism of pollination in the American plant differs markedly from 

 that described by Koerner, and widely copied from his Pflamerileben. The 

 chief points are that the staminate flowers float on their recurved sepals, till 



