262 JOUENAL OF THE KOYAL HORTICULTURAL SOCIETY. 



Botany at Queen Margaret College, Glasgow University. With Plates I., 

 II., and III. (Ann. Bot. vol. xvi., No. 61, p. 23 ; March 1902).—" The 



difference of opinion which exists among investigators who have studied 

 the Ophioglossaccce as to the phylogeny of this small group of vascular 

 Cryptogams is well known. Paleobotany has not afforded decisive indica- 

 tions of connecting links with either the Filicineous or the Lycopodineous 

 phylum, and comparative study of the existing forms is alone available 

 in the solution of the problem." This study the author has entered 

 upon in the present paper, where only the evidence of the gametophyte 

 is considered. It appears that he himself was the first to describe the 

 prothallus of Helminthostachys zeylanica. (See Proc. Boy. Soc. vol. lxviii. 

 1901, p. 405.) The prothallus is therefore known of all three genera 

 which compose the sub-order Ophioglossacece, viz. Ophioglossum, Helmin- 

 thostachys, and Botrychium. 



Writing of Ophioglossum pendulum the author says that " after a 

 year and a half the largest prothallus consisted of but three cells and 

 were still partially enclosed in the exospore. A most remarkable circum- 

 stance in connection with the prothallus of this Fern, and also of 

 Helminthostachys, is the possession of a symbiotic fungus which grows 

 within their tissues. In the latter case it dies about the time that the 

 sexual region begins to elongate. It will be interesting to gardeners that 

 in each case the prothallus is subterranean, that of Helminthostachys 

 growing at a depth of two inches. The author remarks that the 

 prothalli of the three living genera of the Ophioglossacece, while differing 

 in details, present essential points of agreement with one another. He 

 does not think that there is relationship with the Lycopodiales. " It 

 does not appear too much to say that while some general resemblances 

 standing in relation to similar modes of life can be traced there are no 

 characters, the morphological value of which is attested by constancy 

 through obviously allied groups, indicating affinity between the two. On 

 the other hand, important points of difference exist in the type of 

 symmetry, in the sexual organs, and in the embryogeny. ... It would 

 appear that the available evidence points to the origin of the type of 

 prothallus found in the Ophioglossaccce from forms not unlike the gameto- 

 phyte of the existing Marattiacece, though possibly belonging to a more 

 primitive group." This important paper is illustrated by seventy figures. 



B. I. L. 



Navel Oranges. 



Orange, Pleiotaxy of Gynaecium in. By Sir William T. Thisel- 

 ton-Dyer (Ann. Bot. vol. xvi., No. 61, p. 154 ; March 1902).— This note 

 is of considerable interest in view of the present sale in the markets of 

 the ' Calif ornian Navel Orange,' * a peculiar variety of firm flesh and 

 distinctive flavour, possessing a conformation at the top of the fruit which 

 justifies the title. This variety is alluded to, but the note refers, in the 

 first place, to an abnormal fruit sent to the author and illustrated on 

 Plate IX. " In this case the axis has been prolonged and has given rise 

 to another series of carpels, forming a smaller fruit, which is entirely 



* The original tree from which the whole of the trees in California have been 

 derived is said still to exist in the Botanic Gardens at Washington. 



