LINNEAIf SOCIETY OP LONDON". 47 



the combined iuflueuce of warmth and light on the duration of the 

 annual phenomena of vegetation. These investigations were 

 brought out in Bugler's ' Botanische Jahrbiicher ; ' where also 

 Hildebrand has a memoir on the similar topics of the duration of 

 life and methods of plant-growth, with theii* causes and develop- 

 ment. Dr. Pfitzer, of Heidelberg, who had previously published 

 a sketch of his views concerning the practicability of classifying 

 Orchids according to their habits of growth, has brought out a 

 sumptuous folio in exposition of his theme. Like nearly every 

 writer who has treated of Orchids, the work is printed ia large 

 type and on luxuriant jiaper, which greatly enhances the cost 

 to the ordinary student. Two subjects, the Victoria regia and 

 Orchids, seem to impel authors to make use of the largest paper 

 and print. Last, but far from least, are the two papers of the late 

 Charles Darwin, which, although they will fairly coine into next 

 year's Address, as they will not be issued for a few weeks, yet, 

 with the remembrance of the worker taken from us so lately, I 

 cannot refrain from alluding to them. Their subject was on the 

 action of carbonate of ammonia on the roots and chlorophyll- 

 bodies of plants. The woodblocks to illustrate these papers had 

 been approved by the author before his death. 



Systematic botany next claiming our attention, I will first men- 

 tion the issue of the third volume of MM. DeCandoIles' ' Mono- 

 graphiae.' The most important groups monographed in this 

 volume are the Commelinacese by our Councillor, Mr. C. B. 

 Clarke, a worthy continuation of his labours on the Bengal 

 plants of that Order; and the Cucurbitacese by M. Cogniaux, 

 the latter occupying more than GOO of the large 8vo pages. Dr. 

 Luerssen's ' Medicinisch-pharmaceutische Botanik ' has been 

 carried on ; as most know, in spite of its title, it is a systematic 

 work of an important type. 



Dr. Buchenau, of Bremen, has made some remarks on Alisma- 

 ceae, Butomaceag, and Juncaginese in Engler's ' Jahrbiicher; ' these 

 Orders have also been monographed by M. Micheli in the volume 

 of DeCandoIles' ' Monographise ' just mentioned. Mr. Baker 

 has drawn up a synopsis of the genus Grinum in the ' Grardener's 

 Chronicle,' to which last week he has added another s])ecies, de- 

 scribed from a drawing by Miss North in the gallery at Kew. Mr. 

 Maw, in the same Journal, has published diagnoses in English of 

 the genus Crocus, as a forerunner of his elaborate treatise on the 

 genus to which he has consecrated so much time and pains. 

 Baron Ferd. von Mueller is continuing his description of the 

 genus Eucali/pUis,t\\e eighth decade having reached this country 

 only yesterday (May 23rd). Mr. Bentham has published in our 

 Journal a sketch of the classification of grasses he purposes adopt- 

 ing in the forthcoming part of the ' Genera Plantarum.' Dr. Emil 

 Koehne has published his monograph of Lythraceaj in Engler's 

 'Jahrbiicher;' and in that Journal will also be found an article on 

 Valerianacete. Before quitting this portion of the subject, I may 



