700 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



xxxiv., No. 1, p. 75).— Karsten emphasises features resembling Gymno- 

 sperms, expressing his belief that the Angiosperms are derived from the 

 latter, Gnctum being the point of contact. At the time of fertilisation 

 in Juglans, the union of the carpels is delayed, thus leaving the ovules 

 exposed, resembling Gnctum. He bases his argument upon embryological 

 characters, and the most important points are summed up in the following 

 comparison of the embryo-sacs of Gnctum and the Angiosperms : — 



Gnetum. Angiosperms. 



Prothallium in lower part . . . Antipodals. 



Egg-cells Egg-cell and synergids. 



Endosperm nuclei ..... Polar nuclei. 



The stimulus to development of \ ( The stimulus to development of the 



embryo and endosperm by fertilisation 1 embryo by fertilisation of the egg ; and 



of at least two egg-cells . . . J development of endosperm by vegetative 



) 1 reproduction. 



G. H. 



Contractile Root-power. 



Liliaceae, Californian, Physiological Observations on the 

 Subterranean Organs of. By A. Rimbach (Bot. Gaz. xxxiii. No. 6, 

 p. 401 ; 1 pi.). — The subject of this paper is the contractile power of the 

 roots, by means of which the bulb or rhizome is carried downwards. The 

 author arranges the ten plants described as follows : — The first group 

 includes Clinton ia, Prosartes and Fritillaria. In these the rhizome 

 alone, by its movement of growth, determines the location of the plant in 

 the earth. It develops horizontally, and is not influenced in a mechanical 

 way by the roots, which are not contractile. 



The second group is formed by Lilium, Scoliopus, and Trillium. Here 

 the growth of the horizontally developing rhizome determines in a much 

 smaller degree the location of the plant. In general, the influence of the 

 contractile roots prevails in fixing the position of the rhizome. 



The third group contains Zygadcnus, Chlorogalum, Calochortus, and 

 Broduca. In these the rhizome develops vertically, and the contractile 

 roots determine almost exclusively the position of the plant. 



Lastly, in Clintonia, Prosartes, Fritillaria, Lilium, Scoliopus, Trillium, 

 and Zj/gadenus, the roots are all of the same kind ; whereas in Chloro- 

 galum, Calochortus, and Brodicea there takes place a division of labour 

 between nutritive and contractile roots.— G. H. 



Linnean Species. 



Linnean Specific Names, The Use of. By Henry & James Groves 

 (Journ. Linn. Sac, Bot. vol. xxxv. p. 368 ; July 21, 1902.) — The authors 

 say that " the Linnean species fall roughly into three groups : those 

 applied to distinct species fairly well understood in Linnrcus's time and 

 still generally accepted ; these which are now considered to include two 

 or more species combined by Linnaeus ; and those about which there is 

 more or less doubt as to the proper application." As to the first group 

 there is little to be said. In regard to the second group, after taking the 

 arguments on both sides into consideration, the conclusion is come to 

 thai the most satisfactory plan is to apply the name to the species which, 



