260 



SCIENCE. 



[N. S. Vol. XVII. No. 424. 



botanical region, although not closely 

 limited from the adjacent lands. In this 

 respect it contrasts with the Arctic regions, 

 Avhich have few peculiar forms. We may 

 cite among its characteristic forms species 

 of Ramadeyas, Chusquea, Philesia, Lapa- 

 geria, Chlorcea, Arjona, lodina, Acmna, 

 Patagonium, Schinus, forms of Verbena, 

 Pernettya, Benthamiella, Acicarpha, Azo- 

 rella, Nassauvia, Peresiaj also remarkable 

 cases of discontinuity as Drimys and 

 Veronica elUptica. 



Nuclear and Cell Division in Diplophrys 

 stercorea Cienk. : Edgab "W. Olive, Har- 

 vard University, Cambridge, Mass. 

 Diplophrys stercorea is an organism be- 

 longing to the Labyrinthuleae, a group on 

 the border line between the plant and ani- 

 mal kingdoms. It passes through two 

 stages in its life-cycle— a vegetative stage 

 in which the spindle-shaped individuals live 

 separate and distinct from one another 

 and a resting stage in which many indi- 

 viduals crawl to definite centers and there 

 heap up in stalked, orange-colored colonies, 

 visible to the naked eye. During the ac- 

 tive vegetative state, the naked cells creep 

 about over a nutrient substratum, being 

 probably propelled by the extremely deli- 

 cate, fine pseudopodia which they bear at 

 the almost opposite poles of the spindle. 

 The individuals in this condition each con- 

 tain usually one yellowish oil body, which 

 lies in the cytoplasm close beside the nu- 

 cleus and which breaks up into minute 

 granules during active movement or dur- 

 ing nuclear division. The nucleus, which 

 is plainly visible in the living organism, 

 is of simple type, consisting of a single 

 spherical chromatin mass, or karyosome, 

 surrounded by karyolymph, the whole en- 

 closed within a membrane. During nu- 

 clear division, the karyosome divides by 

 simple constriction into two equal parts. 

 Division of the naked spindle-shaped cell 



results from the progressive cleavage of a 

 fission plane, which starts at one side and 

 travels transversely across the cell at an 

 oblique angle. This oblique plane of fis- 

 sion is unusual, since longitudinal or trans- 

 verse fission is the rule among unicellular 

 forms. The oil bodies are equally repre- 

 sented in the two daughter cells, and in 

 the subsequent resting condition they usu- 

 ally become aggregated into one refractive 

 yellow mass. 



On the Behavior of Certain Yeast Organ- 

 isms in Pure and Mixed Cultures: "Wm. 

 B. Alwood, Blacksburg, Va. 

 This paper treats briefly of the physio- 

 logical activities of yeast organisms isolated 

 from the fruits of apple, and then sown as 

 pure and also as mixed cultures in an apple 

 must of known chemical composition. The 

 results obtained are illustrated by two 

 graphic charts. 



The Desert Botanical Laboratory of the 

 Carnegie Institution: D. T. MacDougal, 

 New York Botanical Garden. 

 A notice in regard to this laboratory 

 has already been published in Science. 

 Dr. MacDougal stated in greater, detail 

 the purposes and scope of the laboratory. 

 President Gilman, Professor McGee, Pro- 

 fessor Toumey and others took part in the 

 discussion. 



The Pines of the Isle of Pines: W. W. 



RowLEE, Ithaca, N. Y. 



A taxonomic discussion of the West In- 

 dian hard pines and a comparison of them 

 with the species of the Gulf states. 



A new species, Pinus recurvatus, is de- 

 scribed and commented upon. The eco- 

 logical significance of the dense summer 

 wood of these species is ascribed to the 

 xerophytic conditions under which the 

 plants exist. Specimens and photographs 

 were used to illustrate the paper. 



