6-4 SUMMARY OF CURRENT RESEARCHES RELATING TO 



kgrm.). In neither of these two latter was the reaction with emulsin 

 obtained, showing the absence in these organs of a glucoside which is 

 decomposed by that ferment. 



Poisonous Properties of Lolium temulentum.* — L. Micheletti con- 

 firms the observations of Guerin and Nestler that the seeds of Lolium 

 temulentum always contain a poisonous principle, due to the presence of 

 a fungus-mycele. 



Poisonous Principle in the Mistletoe, f — E.Laurent finds in seed- 

 ling plants of mistletoe a substance which is toxic to the pear-tree. It 

 occurs also in the pulp of the berry, and is, no doubt, secreted by the 

 embryo. 



(3) Structure of Tissues. 



Resin-Receptacle in the Polypodiaceae and in some Phanerogams.^ 

 — D. F. Hohlke finds the formation of resin to be a very widely distributed 

 phenomenon in ferns (Polypodiaceae). The resin-forming organs are 

 always glands ; and these may be either external or internal. The 

 resin is usually a product of transformation of a layer of the cell-wall, 

 being formed between the cuticle and the inner layer ; less often it is 

 excreted by the cell-membrane. The internal glands occur in a large 

 number of species, and on different organs ; they are almost invariably 

 unicellular trichomic structures; the external glands often consist of a 

 number of cells, but the head is always unicellular. 



In the flowering plants examined — Senecio viscosus, Ononis spinosa, 

 Pelargonium zonale, Erodium cicutarium, the author finds, in opposition 

 to the statement of Behrens, that the resin is also always a product of 

 the disintegration of a layer of the cell-wall. 



Persistence of Leaf-traces.§— Sir W. T. Thiselton-Dyer finds the 

 persistence of leaf-traces already recorded by him not to be confined 

 to Araucaria, but to occur also in other genera of the Araucarieaa. He 

 has found it in Agathis australis, and in Cunninghamia sinensis, but not 

 in Sciadopitys verticillata. 



C4) Structure of Organs. 



Polychroism of Flowers.|| — By this term W. Taliew expresses the 

 tendency of a species to produce flowers of more than one colour. The 

 differently coloured flowers may either be produced on the same plant, as 

 Pulmonaria officinalis and Orobus vcrnus, or — which is much more com- 

 mon — on different individuals. Of this a number of examples are 

 given: — Anemone ranunculoides, A. patens, Iris pumila, Tulipa Ges- 

 neriana, Myosotis amoena, Primula acaulis, Matthiola odoratissima. 



Distribution of the Sexes in the Compositae.1T — M. von Uexhiill- 

 Gyllenband treats in great detail of the distribution of the sexes in the 

 capitule of the Composite, his conclusions being founded on observations 



* Bull. Soc. Bot. Ital, 1901, pp. 215-7. Cf. this Journal, 1899, p. 191. 

 + Comptes Rendus, exxxiii. (1901) pp. 959-G1. 

 t Beih. z. Bot. Centralbl., xi. (1901) pp. 8-45 (3 pis.). 

 § Ann. Bot., xv. (1901) pp. 547-8. Cf. this Journal, 1901, p. G60. 

 || Beih. z. Bot. Centralbl., x. (1901) pp. 562-4. 



Tf Bibliotheca Botanica, lii. (1901) SO pp., 2 pis., and 2 tigs. See Bot. Ztg. lix. 

 (1901) 2 t0 Abt, p. 262. 



