156 BOOK-NOTES, NEWS, ETC. 



exhibit a relationship to Amhlystegium riparium. There are in all 

 forty-two species ; and these are grouped into six sections, of which 

 two — Euauihlystegium and Caw})ijliadelphus, containing thirteen and 

 five species respectively — were included in part xvii. In the present 

 part comes the extremely difficult section Drepcmocladus or Har- 

 pidium, to which Dr. Braithwaite attaches the anomalous Thiddium 

 decipiens De Not. This section contains twelve species. Then 

 follow Scorpidium with one species, Hijf/roJu/pnum or Limnoblum with 

 six, and Calliergon with five, three of which have failed to secure 

 accommodation in part xviii. Dr. Braithwaite is much to be con- 

 gratulated upon the completion of one of the most troublesome 

 portions of his undertaking. — A. G. 



At the meeting of the Linnean Society on Feb. 3rd, Mr. W. C. 

 Worsdell read a paper on " The Comparative Anatomy of certain 

 Genera of the CijcadacecE.'" The chief points touched upon were : — 

 In Cycas, the conduplicate vernation and arrangement of the bundles 

 in the fleshy hypog^eal cotyledons, the secondary extrafascicular 

 rings, the concentric cortical strands, and, in one species, the 

 peculiar concentric structure of the leaf-traces, in the stem, and in 

 the hypocotyl some curious concentric strands running obliquely 

 out from the cylinder, and, in a small seedling, the secondary 

 vascular cylinders lying outside the normal stele ; in the seedling of 

 Stangerla paradoxa the small primary concentric bundles in the stalk 

 common to the two cotyledons, which both higher up and lower 

 down become collateral, and in the adult stem the occurrence of a 

 secondary concentric strand in the periphery of the cortex, which 

 appeared to be the remnant of a once normal system of nude strands ; 

 and in Ceratozamia mexicana the vertical succession through the pith 

 of a large stem of effete peduncular cylinders, the peduncles which 

 successively terminate the stem being in turn pushed to one side and 

 their basal region enclosed by a lateral shoot which continues the 

 main vegetative axis. In conclusion the author endeavoured to show 

 that certain characters in the vegetative structure of these plants 

 showed them to be nearly allied to, or descended from, certain fossil 

 fern-like plants, notably the Medulloseie, and these characters were : 

 the extrafascicular zones in tlie stem of Cijcas, which really repre- 

 sent the outer portion of the flattened concentric strands in the stem 

 of the Medullosepe, the inner portion of which has died out ; and all 

 the various concentric structures above-mentioned. For the type of 

 structure prevailing in the ancestors of the Cycads would have been 

 the concentric, whereas in their descendants it is the collateral. 

 The significant outcome of this study is to form, in the vegetative 

 characters of these plants, a connecting link, over and above that 

 already aflbrded by the discovery of spermatozoids in Cycas and 

 Ginkgo, between "flowering" and "flowerless" plants. 



At the meeting of the Linnean Society on Feb. 17th, Mr. F. N. 

 Williams, F.L.S., read a paper on Arenaria, one of the larger genera 

 of Caryophyllacea, which now includes a considerable number of 

 species. Alsine and others, usually included as sections of the 

 genus, he thought should be regarded as distinct genera; Alsine 



