76 SUMMARY OF CURRENT RESEARCHES RELATING TO 



in Hevea brasiliensis, Maniliot Glaziovii, 'Phaseolus lunatus (leaves), 

 Indigo/era galegoides (leaves), and, in smaller quantities, in the leaves of 

 many other plants. 



Calcium Oxalate in the Pericarp Tof the TJmbelliferae.* — Dr. J. 

 Rompel gives details with regard to the presence of crystals of calcium 

 oxalate in the pericarp of Umbelliferse, and its value for the purpose of 

 classification ; 220 species, belonging to nearly 100 genera, having been 

 examined. 



He finds that the presence of these crystals, and still more their mode 

 of distribution, is often characteristic of natural groups. The various 

 modes of deposit may be classed under three types — those of Hydro- 

 cotyle, of Sanicula, and of Scandix. The Hydrocotyle-type — characterised 

 by an endocarp composed of an inner hard layer and an outer coat 

 c staining crystals — occurs without exception in the tribes Hydrocotyleae 

 and MulineaB. Erigenia must be excluded from, Hermcts, Activotus, and 

 Asirotricha included in this section of the order. The Sanieula-type — 

 in which the clusters of crystals are usually grouped at particular spots 

 of the pericarp, and deposited in parenchymatous cells — is characteristic 

 of the tribe Sanieulese, from which Arctopus and Lagcecia must be ex- 

 cludcd, while Lichtensieinia and other allied South African genera must 

 be placed in it. The Scandix-type is characterised by the occurrence 

 of usually single crystals in several layers of cells along the commissure 

 and around the carpophore, and is universal in the Seandicinere and 

 Caucalineae. 



Calcium Oxalate in the Embryo of Papilionacese-t— According to 

 Sig. J. Caldarera Ca&tranovo, the occurrence of crystals of calcium 

 oxalate in the embryo of the Papilionacese is only exceptional. Jt may 

 occur either in the form of iiosanoff 's crystals, or as an enclosure in the 

 aleurone grains, as sphjeritcs, single crystals, or clusters. They are 

 located in the parencbyme of the cotyledons, occasionally in the aleurone 

 grains of the epidermal cells ; never in the plumule or radicle. Crystals 

 of calcium oxalate are formed especially when there is abundance of 

 aleurone and but little or no starch. 



Alleged Digestive Enzyme of Drosera.} — M. Raphael Dubois re- 

 affirms his statement that, in the tentacles of Drosera (longifolia), there 

 is, as is the case also with the pitchers of Nepenthes, no zymase capable 

 of digesting albuminoids. 



(3) Structure of Tissues. 



Spiral Thickenings in the Water- conducting Elements.§ — Dr. M. 

 Koernicke describes the peculiar spiral thickenings in the tracheids of 

 Viscum album. They present the peculiarity that the thickening-band 

 is not directly attached along its whole length to the wall of the vessel ; 

 but the main spiral (Kepfspirale) is fixed on a narrow cross-piece, the 

 " foot-spiral," which is itself attached to the wall of the tracheid. The 

 two portions of the spiral present different staining reactions, which are 

 described at length. 



* SB. k. Akad. Wi&s. Wien, civ. (1895) pp. 417-74 (2 pis.). 



t Lab. 1st. Bot. Univ. Catania, 1898, 38 pp. anrl 1 pi. See Bot. Centralbl., xxix. 

 (1899) j). 199. X Ann. Soc. Linn. Lyon, xlv. (1899) pp. 79-80. 



$ SB. Niederrhein. Gesell. Nat. u. Heilk. Bonn, 1899, l ,e Haltte, pp. 1-10 (1 fig> 



