Linna?an Society. 149 



Chrysanthemum alpinum, Gentiana Bavarica, Ranunculus glacialis, 

 Saxifraga bryoides, S. oppositifolia, Silene acaulis, &c. &c. The 

 extreme limit of Mosses is in general little above that of phaneroga- 

 mous plants. The last Lichens are to be found on the highest summits 

 of the Alps, attached to projecting rocks, without any limitation of 

 height. The number of species and varieties, up to this time between 

 40 and 45 species, which have been found in the Alps between 

 10,000 and 14,780 Paris feet, is not inconsiderable, but this vege- 

 tation is limited to very few spots, surrounded by extensive masse* 

 of snow. Among the Lecidece, Parmelice and Umbilicaria, collected 

 by Saussure, Agassiz, and themselves, on the highest localities, Dr. 

 Schlagintweit enumerated Lecidea geographica, L. confluens, Par- 

 melia elegans, P. varia, P. polytropa, Umbilicaria proboscidea (3. cy- 

 lindrica, &c. 



December 17. — Robert Brown, Esq., President, in the Chair. 



Read the conclusion of Mr. Benjamin Clarke's " Memoir on the 

 Position of the Carpels when two and when single, including out- 

 lines of a new Method of Arrangement of the Orders of Exogens, 

 and observations on the structure of Ovaries consisting of a single 

 Carpel." 



In this memoir Mr. Clarke details the results of his observations 

 on the position of single and double carpella in reference to axis, 

 with the view of ascertaining the mode in which the reduction of 

 the carpella from a higher number takes place, and the value of the 

 characters thus obtained in the formation of a natural arrangement 

 of plants. He commences with dicarpous ovaries, in which he ob- 

 serves three different positions in relation to axis : 1st, right and 

 left, resulting generally (as he believes to be shown by an examina- 

 tion of the genus Car ex and of certain Malpighiacece and Euphorbiacece) 

 from the suppression of a third and usually posterior carpellum, but 

 occasionally also (as for example in Lonicera, Fortunea, Diosma, and 

 probably Cruciferce) from the abortion of the anterior and posterior 

 carpella of an ovary originally consisting of four divisions ; 2ndly, an- 

 terior and posterior, resulting in Houttuynia cordata from the disap- 

 pearance of one of the lateral carpella and the displacement of the 

 other so as to become opposed to the persistent posterior carpellum ; 

 in Agrimonia and Spircea (when dicarpous) from a similar sup- 

 pression ; as also in reduced fruits of Reseda luteola, &c. ; 3rdly, ob- 

 lique, which he describes as of frequent occurrence both in plants in 

 which the carpella are generally anterior and posterior, and in those 

 in which they are as predominantly right and left, and which he sup- 

 poses to arise from the remaining lateral carpellum of a tricarpous 

 ovary retaining nearly its original position when the other lateral 

 carpellum has disappeared, in consequence of which the posterior 

 carpellum is somewhat displaced, becoming obliquely posterior. He 

 regards the single carpellum as the result of the non- development 

 of one of the carpella of a dicarpous ovarium, and its position may 

 consequently vary in three different ways ; 1st, anterior, as occurs 



