382 Chronicles of Science. [July, 
Seeds of Juncus and Luzula.—In the ‘ Botanische Zeitung’ 
is a paper by Dr. F. Buchenau, of Bremen, “On the Sculpture- 
markings of the Testa of the Seeds in the German Species of these 
Genera.” An English translation appears in Seemann’s ‘ Journal 
of Botany’ for May. Certain points of difference connected with 
the seeds have long been used as sectional characters in both 
genera ; but the peculiar mouldings of the external seed-coat do not 
seem to have been systematically examined by any botanist before 
Dr. Buchenau. At his suggestion, however, Dr. Engelmann of 
St. Louis looked at this pomt in the North American species 
of Juncus, and in his recently published “revision” of them * has 
founded three sections on the characters presented. In the present 
paper, Dr. Buchenau, though taking exception to some of Dr. Engel-. 
mann’s terms, generally adopts his divisions. The characters of 
the testa of 31 species of Juncus are given ag seen under a power 
of 50 diameters in dried herbarium specimens of perfectly ripe 
seeds. It appears that the testa is either costate, ¢7.e. marked with 
prominent longitudinal ribs, connected only by few and incon- 
spicuous ones, or reticulate, of which there are two kinds. In one 
the cost are still prominent, but connected by equally prominent 
transyerse ridges, in the other the costz are inconspicuous and wavy 
or angular, whilst the transverse ribs appear very prominently (called 
transtilla) ; in both cases reticulations are formed, and are often 
marked with more delicate lines (lineolx). The characters are 
said to be constant. 
In Luzula there is less variety, the testa being reticulate in a 
more or legs regular or longitudinal manner in all the species (12) 
examined. 
Seedless Raisins.—Mr. T. Mechan, in the ‘ Proceedings of the 
Philadelphia Academy,’ calls attention to the fact that the ordinary 
vine of Hurope is frequently found in a barren state, bearing only 
male flowers, and he suggests that the seedless raisins and currants 
so much prized may be the fruit of purely female plants, ripened, 
though never fertilized. It appears, however, that as yet purely 
female plants have never been observed by botanists. 
Discoloration of the Sea—Some interesting facts “On the 
Nature of the Discoloration of the Arctic Seas” were communicated 
last year to the Kdinburgh Botanical Society by Mr. Robert Brown. 
The paper has ,been printed in Seemann’s ‘Journal of Botany,’ 
Arctic voyagers have long ago noticed the sea in Davis’s Straits, 
Baffin’s Bay, and other parts, to be dark olive-green, or even black 
in colour, and the appearance has been considered to be due to the 
presence in it of great multitudes of minute animals (Meduse, 
Entomostraca, and Pteropoda.) Mr. Brown noticed, however, that 
* “Transactions of the Academy of Sciences of St. Louis.’ 
