822 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Secreting System of Hydrocotyle.* — According to M. P. Vuillo- 

 min, tho absence of oleiforous canals from tho root, pcricyclo, and 

 tho cortical and medullary parenchyma of Hydrocotyle vulgaris, as 

 contrasted with other mombers of the Umbellifcra), is due to its small 

 size and aquatic habit. In other species of the genus the suppression 

 is not nearly so complotc. 



Laticiferous Vessels as Assimilating Organs.f — An examination 

 by Sigg. R. Pirotta and F. Marcatili of tho laticiferous system of a 

 number of species of Ficus, leads them to the conclusion that these 

 vessels aro of no small importance in tho direct conduction of tho 

 products of assimilation, in many species tho latex-tubes which 

 enter the lamina of the leaf from the petiole accompany the vascular 

 bundles to their extremities, and often replace thoir conducting 

 parenchyma ; while in other cases these tubes arc partially detached 

 from the ends of the bundles, and run independently in the mcsophyll 

 as far as the pallisadc-tissuc. 



Ducts in Chestnut- wood. J — Mr. P. H. Dudley describes tho 

 structure and mode of formation of the ducts in the wood of the 

 American chestnut (Castanea vesca). In this wood the large ducts in 

 tho inner portion of each annual ring are very conspicuous, attracting 

 attention at once in the transverse and radial sections. They arc 

 formed in one, two, or three quite distinct concentric rows in tho 

 early spring growth of each annual ring. 



Superficial Extent of the Underground Parts of Plants. § — 

 M. A. Girard proposes a method of ascertaining the superficies of 

 roots by placing them on a metal plate and throwing on them flowers 

 of sulphur. They aro then beaten until no more sulphur becomes 

 detacbecl. The portion still adhering forms a coating of a uniform 

 thickness of about 0- 1-0*2 mm.; this can be detached by a 10 per 

 cent, solution of alcohol, and weighed. 



Non-chlorophyllaceous Saprophytes. || — Herr F. Jobow describes 

 tbo chief points of morphological structure connected with tho 

 biology of several West Indian saprophytes destitute of chlorophyll, 

 viz. Burmannia and Apteria belonging to Burmanniacese, Wull- 

 schlsegelia to Orchideae, and Voyria to Gentianacea;. 



All these genera have minute seeds with imperfectly developed 

 embryo. In Burmannia the embryo lies at the apex of the endosperm, 

 and consists of from three to six, or, in B. capitata, of ten cells. 

 WullscJdsegelia differs in no respect from other orchids. In Voyria 

 the embryo-sac originates from the uppermost of the four daughter- 

 cells of the mother-cell of the embryo-sac ; the anatropous structure 

 of tho ovule being manifested at its very earliest period, and not de- 

 veloping later. The ovule is naked without any integument. The 



* Bull. Soc. Bot. France, xxxii. (1885) Sess. Extraord., pp. ci.-civ. 

 t Ann. R. 1st. Bot. Roma, ii. (1885) pp. 48-9. See Bot. CentralbL, xxvi. 

 (1886) p. 212. 



J Bull. Torrcy Bot. Club, xiii. (1S86) pp. 91-2. 



§ Comptcs Rcndus, xcii. (1886) pp. 1257-60. 



|| Pringaheim's Jahrb. f. Wiss. Bot., xv. (1885) pp. 115-40 (1 pis.). 



