NOTES AND ABSTRACTS. 



813 



Departement de TAgriculture des Indes Neerlandaises, " No. xxi. 1909, 

 which is reprinted in this number of the Jour. Soc. Nat. Hort. The 

 palms have been studied and the names verified by Professor Beccari, 

 of Florence.— M. L. H. 



Pandanus, The Pneumatophores of. By J. 0. Schoute 

 {Ann. Jard. Bot. Buit. 3rd supp. 1st part, 1910, pp. 216-220; with 

 1 plate and 2 text-figures). — Pneumatophores are negatively geotropic 

 roots which bear air-pores (pneumathodes) upon them. Warburg had 

 denied their presence in the Pandanaceae, but Schoute, like Karsten 

 before him, finds them to occur in several species of Pandanus. The 

 little pockets formed by the clasping leaf-bases and the stem of 

 Pandanus are constantly filled with water or wet humus, so that the 

 stem of this region is shut off from the surrounding atmosphere and 

 its respiration endangered. By the production of numerous pneu- 

 matophores from this part of the stem the difficulty is met and an 

 adequate exchange of gases ensured for the stem-tissues. — R. B. 



Parasitism among* Fungri. By E. W. Schmidt (Zeitschr. f. 

 Pflanzenkrank. xix. 1909, Heft. 3, p. 129). — This paper opens with a 

 discussion of the steps or stages that have to be passed through during 

 the process of infection of a host plant by a parasitic fungus. In the 

 case of saprophytic fungi it has already been proved that their hyphse 

 are sensitive to chemical substances and exhibit the phenomenon of 

 chemotropism. The author sets out to ascertain whether this is also 

 true for parasitic fungi. Using a species of Phyllosticta, parasitic on 

 pear leaves, he finds that the hyphse are attracted from a substratum 

 poor in nutritive substances towards one rich in them (plum juice), the 

 two media being separated from each other by a celluloidin membrane. 

 Further, he finds that the hyphae penetrate and pass through the mem- 

 brane, and in doing so they stain it, probably with some product of 

 excretion, possibly of an enzymatic nature. In the case of the living 

 host cell, however, the author's view is that an outward diffusion of 

 the cell-contents, from the epidermis for example, cannot take place, 

 and chemotropism cannot therefore com»e into play until the fungus, 

 either by excretion of enzymatic or toxic substances or by purely 

 mechanical means, has produced such changes in the epidermal cell 

 as will result in a diffusion to the exterior of the cell-contents. The 

 results of investigations in regard to this point are promised in a future 

 communication. — G. H. P. 



PatPinia triloba {Bot. Mag. tab. 8328).— Nat. ord. Valeri- 

 anaceae. Japan. Herb perennial, 8-16 inches high; leaves palmately 

 i three or five-lobed; cymes three-nate, forming a panicle 5 inches 

 i across; corolla yellow, J inch across. — G. H. 



Peaches as Vineg-ar Stock. By H. 0. Gore {U.S.A. Dep. Agr., 

 ! Bur. Ghem., Circ. 51, Feb. 1910). — In seasons of heavy crops in 

 ' American peach orchards, and especially when hot weather causes the 



