992 SUMMARY OF CURRENT RESEARCHES RELATING TO 



zone. The soctl is covered by tlic endocarp, tlie most external layer of 

 Avbich consists of viscid colls, whicli arc severed at their peripheral 

 (distal) ends when the seed is ejected. Neither the sessile anthers nor 

 the carpels are vascular ; tht; latter are opposite to the segments of the 

 perianth. The author found no adventitious purely vegetative shoots ; 

 lie detected a constant connection of the xylem-vessels of tlie parasite 

 with tlie trachcides of the host (rinus or Jitulperitsy and a cleavage of 

 tlie radial wall of the tracheide of the host by the finest haustoria of the 

 parasite. 



Seeds with Two Integuments.* — IM. 11. Jumelle states that the 

 integuuunt.s of seeds do not generally coincide with those of the ovule. 

 "When the seed has two integuments, these integuments are formed from 

 the external envelope of the ovule, the internal one disappearing. This 

 rule, to whi( h up to the present time the Euphorbiaccfe have been con- 

 sidered au exception, is not however absolute ; the author pointing out 

 two other gioups which form exceptions. These groups are Rosaceae 

 and Kutaceic, in both of which, as in Enphorbiaccfe, the two integu- 

 ments of the ovule persist. In this case these two integuments are 

 separated by the formation of a layer of cork in the region of the 

 chalaza, where they were previously in contact. 



Overlooked Function of many Fruits.f — Prof. C. E. Bessey points 

 out that the green colour of the rind of many fruits is not an original 

 condition, but that the colour makes its appearance during their increase 

 in size. He suggests that this very general development of chlorophyl- 

 lous tissue is for the nutrition of the embryo in the seed. A striking 

 instance is aflforded by many species of elm in which, at the time of 

 flowering, there are no leaves upon the tree, nor do any appear until the 

 fruits are fully grown. 



Trapella, Oliv., a new Genus of Pedalineae.J -Dr. F. W. Oliver 

 describes the structure, develoimient, and affinities of Trapella Oliv., a 

 new genus of Pedalinefe, the single known species, T. sitifmis, growing 

 in China. 



Trapella is an aquatic i)lant with long straggling and simple or 

 sparingly branched stems, which ascend obliquely through, and float on 

 tlie surface of the water. In the axils of the floating leaves, and of the 

 submerged ones for some distance below the surface, flowers are foi'med, 

 which in the former case open just above the surface, but in the latter 

 are cleistogamic. The ovary is bilocular, but the anterior loculus is 

 quite rudimentary. The placentation is axile, and the two ovules are 

 inserted high up in the fore-part of the ovary. Both are pendulous, and 

 apparently anatropous, with superior micropyb'. They arc attached 

 right and left of the median line to the top of the partition separating 

 the reduced and fully developed loculi. The upper ovule, attached on 

 the right side of the median line, is sessile, but the lower one is suspended 

 by a longish funiele. 



In the youngest buds the author was able to investigate, all the 

 organs were already formed. Up to a certain point the developmental 

 history of both upper and lower ovules is identical ; since, however, in 



* Bull. Soc. Bot. France, xxxv. (1888) pp. 302-4. 



t Amcr. Natural., xxii. (1888) p. 581. 



J Ann. of Bot., ii. (1888) pp. 75-112 (5 p's. and 1 fig.). 



