578 Proceedings of the London Horticultural Society. 



they were, in consequence, affected by frost in a much greater degree, than 

 when, from the coldness of a station, they were kept in their ordinary winter 

 condition. 



The temperature of the earth at different depths, during the prevalence of 

 the frost, was mentioned as explaining why so many trees that had heen 

 killed to the ground were afterwards observed to spring up again. In the 

 Society's garden two thermometers were buried in the earth, one at the depth 

 of 1 ft., the other at the depth of 2 ft., and their indications were noted daily, 

 when it was found that the ground was never frozen to the depth of a foot, 

 even while the temperature of the surface was as low as 4|° below zero, and 

 that it did not fall to within 5° of freezing at the depth of 2 ft. during the 

 same period. 



The last subject which had engaged the author's attention was the physical 

 effect of extreme cold upon plants. After noticing the opinions upon this 

 subject, given by Professors Goppert of Breslau and Morren of Liege, and 

 describing various observations which he had himself made, he arrived at the 

 conclusion, that the more important phenomena connected with the action 

 of extreme cold upon plants consist in the distension of cellular succulent 

 parts, often attended by laceration, and always by a destruction of irritability ; 

 the expulsion of air from the aeriferous passages and cells ; the introduction of 

 air into parts intended exclusively to contain fluid ; a chemical decomposition 

 of the tissue and its contents, especially of chlorophyll; a destruction of the 

 vitality of the latex, and a stoppage of the action of its vessels ; and, finally, 

 an obstruction of the interior of the tubes of pleurenchyma, by the distension 

 of their sides. 



This report was stated to contain observations upon between six and seven 

 hundred species and varieties. 



The following objects were exhibited : — From Mr. John Green, gardener 

 to Sir Edmund Antrobus, Bart., a cucumber, and several ver}' fine green- 

 house plants, among which was a beautiful plant of Lucidia gratissima. This 

 charming species, whose perfume is of the most grateful kind, and whose 

 broad heads of flesh-coloured flowers rival those of the hydrangea, was im- 

 ported some years ago, but has gone very much out of cultivation in con- 

 sequence of an erroneous statement that it is hardy. That is not the 

 case, nor was it ever probable that the plant would bear an English winter, 

 for it is only on the smaller and lower mountains of Nepal that it is met with 

 in a wild state ; as on the naked rocks of Nag-Urjoon, Bechiako, and Koola- 

 kan, and on the Pundua hills on the frontier of Sylhet ; in those places it is 

 said to form a tree from 16 ft. to 20 ft. high, with a stem 6 in. in diameter. 

 As it flowers all the year round, this is a most desirable plant for a conser- 

 vatory, or as a shrub of the open border, during the warmer months of 

 summer. 



From Mr. Peter Don, Gardener to James Bateman, Esq., specimens of 

 four kinds of epiphytal Orchidaceae; viz. 1. a new species of Maxillaria ; 

 2.BoibophylIum caseum of Manilla, a little brown-flowered species, named from 

 its smelling strongly of cheese; 3. LaeHia albida, anew Mexican plant, with 

 flowers rivaling the cowslip in their fragrance; and, 4. the rare and beautiful 

 Epidendrum Skinneri. Concerning the latter, Mr. Bateman communicated 

 the following note : — 



" The exquisite beaut}' of the flowers of Epidendrum Skinneri, and the 

 season at which they are produced, render the plant one of singular interest 

 to the lovers of Orchidaceae ; unfortunately, however, it has universally been 

 found extremely difficult to manage. Its flower-spikes, it is true, were always 

 forthcoming, even from the weakest shoots, but the number of flowers which 

 they bore grew less and less each successive season, until at length in too 

 many instances the plant perished altogether. 



" The cause of this ill success in its cultivation was obviously owing to the 

 difficulty in preserving its thick fleshy roots from decay ; for many were uni- 

 formly lost if the plant was kept in a high and damp temperature, or if they 



