922 



JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



If spermagonia and a?cidia represent male and female reproduction 

 organs, a distinct alternation of generations may be regarded as present, 

 the gametophyte generation starting with the uninucleate teleutospore, 

 and the sporophyte with the fertilised cell in the jecidium. — A, D. C. 



Vanda pumila. By W. B. H. (Bot. Mag. t. 7968).— Native of 

 Sikkim. Nat. ord. Orchid ec& ; tribe Vandece. Racemes 3-flowered ; flowers 

 very fragrant, ivory-white, 2 to Z\ inches diam., lip striped with crimson, 

 having an obconical spur. — G. H. 



Variegation contagious (Rev. Hort. p. 402, Sept. 1, 1904).— 

 M. Lindemuth notes numerous instances of variegation being transmitted 

 to stocks by grafts of variegated plants, sometimes to such an extent as 

 to cause entire etiolation and death. — C. T. J). 



Vascular Bundles and Forms of Vessels, Types of. By P. 



Emmanuel Scherer (Beth. Bot. Cent. xvi. pp. 67-110; with 3 tables).— 

 Describes nine types of monocotyledonous vascular bundles, and shows 

 that the structure is altered by the time at which vegetation begins or 

 ceases. Small vessels or tracheids are not always formed at first, for, 

 in the case of some bulbous plants, there is a sudden beginning and 

 short duration of the vegetation period. Annular and spiral vessels 

 allow of longitudinal stretching, and are hence common in young parts of 

 stems, less so in roots. Some roots also appear to show evidence of 

 elongation, but most have porous thickening and a very short growth zone 

 (except aerial roots). One and the same vessel shows different thickenings 

 at different points. The narrow radial vascular bundle in stem and leaf 

 of Scilla bifolia is a mechanical adaptation. The author lays stress on 

 the necessities of supporting the stem, of preventing collapse in the vessels, 

 and of providing for hydrostatic pressure in the root as explaining several 

 structural details. The paper is both suggestive and interesting. 



G. F. S.-E. 



Vascular Bundles of Dicotyledons, Investigations on. By A. 



Col (Ann. Sc. Nat. Bot. xx. pp. 1-281 ; 40 figs.; 1901). — A comparative 

 study of anomalous vascular bundles in Dicotyledons. These bundles 

 may occur in the pith, or in the cortical region outside the normal 

 vascular ring ; they may be bundles with phloem and xylem elements, or 

 they may consist only of phloem. About 150 species are dealt with, and, 

 as many of them are figured, the paper is an exhaustive one. Following 

 the introduction, the first part (pp. 17-97) deals with the Campa?iulaccce. 

 Some species have anomalous bundles in the leaf only, the stem bundles 

 being normal ; other species have anomalous bundles in the stem. The 

 pith bundles in most cases are downward prolongations of bundles of the 

 normal ring, which, if traced downwards, are seen to break away from the 

 ring (generally at the junction of two vascular branches) and to enter the 

 pith ; these medullary bundles may either end blindly, or, more frequently, 

 they return to the normal ring lower down the stem. The second part is 

 a comparison of results obtained for the Gampanulacca with anomalous 

 bundles of other Dicotyledons. A chapter (pp. 99-151) is devoted to 

 anomalous bundles occurring in the leaf only, the stem being normal, 



