216 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Formation of Cork in the Chenopodiacese.* — From an investigation 

 of the process in several genera, Herr B. Lcisering states that, in the 

 ChenopodiaceoB, the cork is formed either beneath the epiderm, or in the 

 lowermost layer of the primary cortex, or in the uppermost layer of 

 the secondary cortex beneath the primary phloem-cells. In the last case 

 it originates either from the first cell which is separated outwardly from 

 the cambium, or from a special layer of the pericambium formed be- 

 fore the extrafascicular cambium. The cork-cells vary in their form 

 from those of an ordinary short-celled parenohyme to parenchymatous 

 fibres exceeding the cambium-cells in length. 



Tracheids and Resin-passages in the Pith of Cephalotaxus.-f— Prof. 

 W. Eothert has detected resin-passages in the pith of several species of 

 Cephalotaxus, resembling those of Salisburia, but hitherto unknown in 

 that position in the Coniferae. In one species, C. koraina sp. n., he has 

 also found in the pith tracheidal parenchymatous cells of very peculiar 

 structure. They have bordered pits and fibrous thickenings like xylem- 

 traoheids, and are empty, but their form completely resembles that of 

 the adjoining parenchymatous cells of the pith. They soon become 

 lignified. Their function is probably the storing up of water. 



C4) Structure of Organs. 



Floral Abnormalities in Linaria spuria.^ — Mr. L. Jost has collected 

 the results of an enormous number of observations on irregular struc- 

 tures in this species, including peloria. He considers them as " belong- 

 ing to the nature of the species," and therefore rather as variations than 

 abnormalities. 



Organs which Secrete Water. — Herr M. v. Minden § states that the 

 secretion of aqueous fluids through the leaves of water-plants takes place 

 either through water-clefts, or through openings destitute of an epitheme. 

 These are usually the result of the absorption of cells lying above the 

 ends of the veins, the last tracheids running free into a small pit at the 

 apex of the leaf ; in floating leaves they are placed on the under side of 

 the leaf. Dicotyledonous aquatic plants have also water-clefts. The 

 water secreted contains large quantities of calcium chloride. Water- 

 clefts are formed on cotyledons at a very early period, their function 

 commencing with the unfolding of the cotyledons. In Tropseolum the 

 water-clefts are larger when the air is very moist. The trichomcs of 

 the leaves of Nicotiana and of Glaux maritima contain an active calcium 

 or magnesium chloride. 



Herr P. Weinrowski || records a number of observations to the same 

 effect on aquatic plants. The openings at the apex of the leaves furnish 

 the means of escape of a current of water laden with mineral sub 

 stances. In Nuphar, Utricularia, and Elodea, pores were detected in the 

 leaf-sheaths. 



Glands of Euphorbia. % — M. L. Gaucher has studied the structure of 

 the glands of the cyathium of Euphorbia. Each gland consists of a loose 



* Ber. Deutscli. Bot. Gescll., xvii. (1899) pp. 243-55 (1 pi.). 



t Tom. cit., pp. 275-90 (1 pi. and 1 fig.). 

 ; % Biol. Centralbl., xix. (1899) pp. 145-95. 

 ' $ Biblioth. Bot., Heit xlvi. (1899) 76 pp. and 7 pis. 



|i Beitr. z. wiss. Bot. (Fiinfstiick), iii. (1899) 41 pp. and 10 figs. See Bot Ztg., 

 lvii. 2 t0 Abt., p. 309. f Joura. de Bot. (Morot), xiii. (1899) pp. 368-70 (1 fig.). 



