140 



SCIENCE. 



[N. S. Vol. XXI. No. 526. 



stock, the method of cultivation or the 

 character of the fertilizer. 



The Development of the Microspores of 

 Vallisneria spiralis: Robert Bradford 

 Wylie. 



The staniiuate flowers of Vallisneria 

 spiralis are borne in clusters, each con- 

 taining often as many as two thousand 

 tiowers surrounded by a spathe. This 

 group of flowers crowded upon the short 

 conical axis is homologous with the single 

 pistillate flower found within its spathe. 

 The individual flowers are very small, sim- 

 ple, and contain usually less than one 

 hundred pollen grains. The staminate 

 flower may therefore be considered as a 

 pollen carrier since the microspores are not 

 shed, but are lost to the stigmas by the 

 pollen producing flowers. In their de- 

 velopment the upper flowers on the axis 

 develop earlier than do the lower ones ; the 

 terminal one is conspicuously more ad- 

 vanced than those adjacent to it. The 

 mature flower always shows four pollen 

 sacs, but a study of their devlopment shows 

 that each of these may arise from a single 

 sporangium or by the fusion of two 

 sporangia. It follows that the single ( ?) 

 stamen may have from four to eight 

 sporangia ; the number seems to vary in- 

 differently even in flowers of the same 

 cluster. The microspores have a single 

 coat which is thin and slightly spinous. 

 The male cells are developed while the 

 spores are still in the sporangium. The 

 male structures clearly show their mor- 

 phology as cells rather than as nuclei only, 

 and remain joined end to end while in the 

 pollen grain. 



Note on the Morj)holog}i of the Cyperacece: 



Amon B. Pi>owman. 



Queva, in his study of the anatomy of 

 certain monocotyledons (Lille, Travaux & 

 Memoires, No. 22, 1899), has described the 

 occurrence of concentric or amphivasal 



fibro-vascular bundles in the nodes of 

 Gloriosa, and has concluded that these 

 bundles are the result of the anastomotic 

 conditions attending the transition of the 

 bundles from the main axis to the axillary 

 branch. Among the Cyperacege it has been 

 found that amphivasal bundles occur in 

 practically all nodes of plants bearing well- 

 developed leaves, whether branches are 

 produced or not; while, on the other hand, 

 in those forms of which the leaves are 

 rudimentary, no amphivasal bundles are 

 present, even in nodes where branches of 

 considerable size are given off. Hence it 

 appears that the occurrence of amphivasal 

 bundles in this group is related to foliar 

 rather than to ramular differentiation of 

 the stelar structures. 



Dictamuus Alhus L. (D. Fraxinella Pers.), 



Gas Plant: W. J. Beal. 



This is an herbaceous perennial of the 

 rue family (Rutaceae). 



The pistil is compound, deeply lobed, 

 consisting of five carpels, each containing 

 two to three seeds, 'each carpel, when ripe, 

 splitting into two valves,' which divide 

 into an outer and an inner layer. In other 

 words, when mature, a considerable portion 

 of the endocarp separates from the exocarp 

 and at once each half begins to make the 

 attempt to twist in opposite directions, 

 much in the manner of the ripe half carpels 

 of a vetch or pea. In this operation the 

 half endocarps press the apical portion of 

 the carpel wide open. A slight ridge on 

 the inner edge of each margin of the carpel 

 prevents for a time the escape of the twist- 

 ing endocarp. The placenta separates into 

 another thin trough-like piece, the margins 

 of which are inside of the endocarp. The 

 two seeds separate from the placenta, 

 which sets loosely over the seeds, prevent- 

 ing them from falling out in case the 

 br'ancli bends down toward the ground. 

 Reeds are torn off" the placenta as this dries, 

 shrinlcing away in the central portion and 



