July 26, 1894J 



NA TURE 



295 



time-honoured Splietwpteris Manielli, with an enormous 

 range, becomes Onychiopsis, representing Oiiychium. 

 A second British form is identified with one hailing from 

 Japan and China ; and a new and pretty Acrostichum, 

 described as Acrostichopteris, completes the list assigned 

 to the vast family of the Polypodiacecv. Tree ferns are 

 more abundant. A remarkable and oft-described species 

 will probably find its final resting-place in Matonidiuin, 

 where it was first placed by Schenk. Another, known from 

 the trunk only, is described under the scarcely satisfac- 

 tory name Protopteris, Presl., preferred by the author 

 to Caulopteris. With its marked affinities, it would have 

 been convenient if this, and perhaps two other species, 

 had been given a generic name suggesting relationship 

 with Dicksonia. 



Spltenopteris is further dismembered by the reference, 

 with a query, of S. Gappcrti to the Schizacea, a family so 

 well represented in the newer Cretaceous and Eocene 

 rocks. It seems again somewhat unfortunate that this 

 species should have received a new generic nam. (under 

 cover, perhaps, of the query) which in no way reveals its 

 presumably strong affinities with Anemia. If nomen- 

 ■clature is to be an aid instead of a stumbling-block, 

 meaningless names should be prohibited. In this 

 particular case Mr. Rufford did not even discover 

 the species, and Ruffordia as a generic name will 

 probably disappear when the highly probable close 

 relationship is incontestably established. Moreover, the 

 author's desire to pay Mr. Rufford a well-earned compli- 

 ment could have been easily gratified among the " genera 

 which afford no trustworthy evidence as to their affinities 

 with existing families," which follow on. Of species fall- 

 ing under this head six are placed in Brongniart's Chido- 

 phlebis, a provisional genus adopted by some of the best 

 palaeobotanists. Two species, one new and the other 

 renamed, represent Sphenopteris. The old Loiichopteris 

 ManlcUi becomes Weichsclia. It is an abundant but 

 distinctly brittle fern, which may prove to be a Glc!che?ita, 



. species so abundant in the newer Cretaceous that it 

 v-ould hardly be unrepresented in the Wealden. The re- 

 maining forms comprise a number of interesting frag- 

 ments, the Oleander-like Taniopteris, Sagenopleris, two 



urious net-veined h3.^n\tn\.%, Dutyophyllum and Micro- 

 dictyon, new to the Wealden of England, and which might 

 have come from the Eocene, so closely do they agree. 

 These suffice, at all events, to show that if we could only 

 meet with some fairly representative leaf-beds, such as 

 abound in newer formations, the Wealden would yield a 

 flora, both varied, and of enormous interest. The descrip- 

 tions conclude with a sufficiently exhaustive discussion 

 of the affinities of tliat difiicult fossil Endogenitcs crosa, 

 which the majority appear agreed to place in Tempskya- 

 This, by the by, as an arborescent fern, would have 

 more properly followed the Cyathea:. 



The whole result shows that a few species which grew on 

 or near where they are found are abundant in the Wealden, 

 while the rest are rare and fragmentary. A large propor- 

 tion possessed separate fertile pinnas, a character main- 

 tained in ancient fern-life down to the Tertiaries, and 

 judging from the preponderance of ferns, the Wealden 

 must be still reckoned in the age of Cryptogams. The 

 next part, dealing with Gymnosperms, will be awaited 

 with interest. 



NO. 1291, VOL. 50] 



OUR BOOK SHELF. 



A Monograph of Lichens found in Britaiti ; being a 



Descriptive Catalogue of the Species in the Herbarium 



of the British Museum. By the Rev. James M. 



Crombie, M.A., F.L.S., F.G.S., &c. Part I. (London : 



Printed by order of the Trustees, 1894.) 

 Mr. Crombie'.s monograph of the British lichens, of 

 which the volume before us forms the first half, is a 

 valuable addition to that splendid series which, issued 

 by the order of the Trustees, form the " Catalogues" of 

 the vast collections preserved in the British Museum. 



Botanists will welcome Mr. Crombie's book, for not- 

 withstanding the works of Leighton and others, the 

 lichens have for the most part been treated with singular 

 neglect. Nor need we seek very far, perhaps, for the 

 reason of this ; their isolation, and the tedious difficulties 

 connected with the task of dealing minutely with the 

 group, have all tended to restrain people from a pursuit 

 which is further hedged about with a formidable and un- 

 wieldy terminology. Other problems more immediately 

 awaiting, or at least inviting, solution, have attracted the 

 majority of investigators, and this notwithstanding the 

 splendid results yielded by the researches of Schwendener 

 and others into the real nature of these plants. And yet 

 the disregard into which the study of lichens has fallen 

 is really not deserved. It is even possible that a clue to 

 the physiological solution of some of the most interesting 

 questions of morphology may ultimately be found 

 amongst these very plants, which from their composite 

 nature can be constructed or altered at the will of the 

 investigator. 



It must, however, be admitted that the taxonomy of 

 lichens is not altogether an inviting study, and Mr. 

 Crombie has rendered a great service in lessening the 

 actual difficulties which necessarily have to be encoun- 

 tered. He begins by providing a glossary (which we 

 think might with advantage have been more extensive), 

 and then, after a synopsis and a conspectus of the groups 

 and genera, occupying a dozen pages in all, he enters at 

 once on the main body of the work. 



The diagnoses are extremely good and, in so far 

 as we have tested them, accurate and distinctive. We 

 cannot, however, help wishing that some stand could 

 have been made against the practice of using incorrect, 

 though possibly conveni'ent, " chemical " formulas {e.g. 

 CaCl for chloride of lime) to denote the reagents so 

 often used in determining the dift'erent species. 



Those who are familiar with the literature will recog- 

 nise Nylander's influence through the book as a whole, 

 and we do not hesitate to express our satisfaction at 

 this ; indeed, in a systematic treatise it is perhaps 

 impossible for some of Nylander's own definitions to be 

 improved on. 



Perhaps the only parts of the book which are at all 

 suggestive of weakness, are the illustrations. These 

 are frequently rather diagrammatic, but at the same 

 time we venture to think they are sometimes not as clear 

 as they might have been, and the impressions are 

 unfortunately not seldom lacking in sharpness and 

 definition. Of course the actual preparations of lichens 

 are often neither very clear nor particularly illuminating ; 

 but these are precisely the defects which admit of remedy 

 in a diagram or a figure. Apart, however, from this 

 point, the book deserves the very highest praise, and its 

 great merits will assuredly cause it to occupy a distin- 

 guished and a permanent position in the literature of 

 hchens. 



Travels in a Tree-top. By Charles Conrad Abbott. 



Pp. 208. (London: Elkin Mathews and John Lane, 



1S94.) 

 The naturalist with poetic fancy, who sees beauty in 

 "all that run, that swim, that fly, that crawl," and pub- 

 lishes his feelings in writings more or less after the style 



