A NEW SPECIES OF DEBARYA.

Abstract

CjOME preserved material of a species of Debarya, which exhibited certain rather interesting features, recently came under notice I submitted a sample to Professor G. S. West, of Birmingham University, and he kindly informed me that it was a new species of the genus allied to D. desmidioides, West.' The material had been fixed in chrom-acetic acid, and transferred to a dilute aqueous solution of glycerine which was allowed to concentrate by evaporation. The preservation was apparently quite good, so that the measurements (necessarily made on this fixed material) should only differ quite negligibly from those of fresh material. The history of the sample is as follows. The sterile filaments, with other Algxe, were collected from stagnant ponds on Sheep's Green, Cambridge, by Mr. T. Elborn, and were transferred to the algal culture tubs kept outside the Cambridge Botany School. Conjugation took place here, and the material was flxed as already stated. DIAGNOSIS. Debarya cruciata sp. nov. Filamentis longis, gracilibus, saepe dissociatis in cellulis singulis; cellulis vegetativis cylindricis, lateribus rectis, diametro 10-18 vel rarius 20-plo longioribus chromatophoris parvis, cum pyrenoidibus 3-7 in seriam unicam dispositis. Conjugatio inter singulas cellulas post dissociationem filamen. tarum. Zygosporis rotundo-quadratis, lateribus levissime retusis, vel rarius convexis, angulis cornutis; cornibus cylindricis, solidis, apicibus rotundis. Long. cell. veg. 60O140,p lat. cell. veg. 6-8,u Long. zygosp. 28-32,u lat. zygosp. 20-24A (sine cornibus). Long. corn. 8-40k lat. corn. 8.12,u The vegetative cells are remarkably delicate (probably the narrowest of the species described for Britain) and relatively long. The gametangia are always isolated single cells of the fllaments, and separated vegetative cells are quite common. The chloroplast is relatively short and narrow and contains from three to seven I West, G. S. Journal of Bot., 1903, p. 39.