28 THE JOURNAL OF INDIAN BOTANY. 



by the red leaf of Acalypha as compared with another sun-plant— Passiflora— 

 and from this he is led to consider (somewhat inconsequently perhaps since 

 the Acalyyha was a sun plant) that a red coloration of the leaves of the 

 undergrowth may possess the same biological significance as that of Red 

 Algae — to enable arc to be made of the green light which filters through 

 the leaves of the forest. A third observation worth nothing is as the so- 

 called drip-tip, which as developed in this forest he considers has not the 

 signifiance ascribed to it by Stahl in Java, the nature of the surface having 

 more effect on drainage than this shape of the leaf. In this connection 

 reference may be directed to a paper by L. S. Sedgwick who offers an ex- 

 planation of the existence of acuminate apices in the ' Indian Forester '. 



P. F. F. 



Prothallia of Lycopodium. 



C. J. Chamberlain, Prothallia and Sporelings of three New Zealand 

 Species. Botanical Gazette, Vol. LXIII, No. 1, pp. 50 — 64. 



The author gives short resume of the literature of the subject, followed by 

 notes on L. laterale, L. oolubile, and L. scraiosum, collected in New Zealand. He 

 finds a green leafy prothallium, with protocorm developed, only in the first, 

 which is a terestial species. The other two species are epiphytic, and the proth- 

 allia are subterranean, with no protocorm. He suggests that this differentiation 

 occurs throughout the genus : and that the green leafy prothallium represents 

 the original type, and that the change to the suprophytic subterranean type 

 occurred in consequence of a delay in germination (some spores require from 

 6 to 8 years) which allowed only those spores that had reached some place 

 of safety, i.e., had been buried, to produce plants. 



E. A. Spressard gives (I.e. pp. 67—78) a very interesting account of the 

 finding of prothallia of L. clavatrum, L. obscurum, L. annotinuv, and L. 

 lucidulum, nearly all quite close together, in an open space near Mar- 

 quette Michigan. They were found only on small knolls covered partly 

 by Polytrichum and partly by a grass, or sometimes almost bare. He suggests 

 as a reason for this that such spores as were carried and fell on these spots 

 were first of all beaten into the ground by rain, then covered by the shifting 

 sand, and finally conveyed to a favourable depth by percolating water. 

 This theory worked well or guide to where to look for the prothallia. 

 The piper establishes the fact that prothallia have been found in America, 

 and announces the discovery of two new species of prothallia— L. obsourwn 

 and L. lucidulum. P. F. F. 



Algae. 



Hybrids of Spirogy ra. — E. N, TranSEAU 1 . (" Hybrids among species of 

 Spirogyra." American Naturalist, March-April 1919) has published a paper 

 recording the results of his experiments on hybridization in species of 

 Spirogyra, especially between S. communis and S. varians, and S. varians 

 and S. porticulis. He finds that hybrid zygospores may be formed between 

 species even though they have very different vegetative and spore charac- 

 ters. The nuclei of the gametes do not fuse until after the zygospore-wall 

 matures. The form of zygospore is determined entirely by the female 

 gamete. Filaments derived from hybrid zygospores show their hybrid 

 character in the dimension of filament, character of sporiferous cell and the 

 form of zygospore. 



