144 Botanical Society of Edinburgh : — 



BOTANICAL SOCIETY OP EDINBURGH. 



June 14, 1855. — Professor Balfour, President, in the Chair. 



Professor Balfour stated that Pontederia elongata had been culti- 

 vated in the Botanic Garden of Edinburgh, and distributed under 

 that name. It seems to be only a variety of P .crassipes, produced by 

 being grown in soil in place of water, The effect of this treatment 

 is to cause the inflated petioles to elongate and lose their globular 

 form. When the plants are put into deep water so as to float, the 

 roots being unable to reach the soil, they assume the proper form 

 of P. crassipes. 



The following papers were read : — 



1 . " Remarks on the Calamites and Sternbergia of the Carboni- 

 ferous Epoch," by Dr. Fleming. 



Dr. Fleming arrived at the following conclusions : — 1. That many 

 species have the original matter, now forming a thin film of coal, 

 smooth on the outside, or not exhibiting externally any traces of 

 joints or longitudinal ribs. 2. From the inside of their woody cylin- 

 ders, now converted into coal, diaphragms proceeded at regular, but 

 occasionally at irregular, intervals, dividing the inside of the hollow 

 stem into a series of chambers. 



These partitions appear to have possessed a very loose texture 

 towards the centre, but become more dense in substance towards 

 their junction with the stem, and usually leave traces of coaly matter 

 at the sides. The jointed character of the casts of the inside, in 

 general all that is noticed by the geologist, is thus referable to the 

 dissepiments, and cannot be regarded as resembling the jointing of a 

 Calamus. 3. The inside of the woody cylinder, although smooth on 

 the outside, was grooved longitudinally in the spaces between the 

 partitions or on the walls of the chambers, and hence the rubbed 

 surfaces of the casts. 4. The stem, unlike Stigmaria and Lepido- 

 dendroUi had no woody axis, nor dense medullary sheath. 



The author next exhibited specimens of Sternbergia^ displaying, 

 like the Calamite, the external cylinder of coal with a smooth surface, 

 and giving no indication of the internal arrangements. The inside 

 exhibited diaphragms having the same origin as in the Calamite, but 

 less regularly disposed, frequently wanting, and giving to the surface 

 of the cast, not a distinctly jointed, but a transversely crumpled ap- 

 pearance. He concluded, by stating that, from the smooth surface, 

 and thickness of the coaly matter into which the plant had been con- 

 verted, joined to its independent or detached condition in the rocks, 

 it could not be regarded as the remains of a discoid pith, but, like 

 the Calamite, as a plant which had a hollow stalk, the cavity divided 

 into chambers by transverse partitions, the remains of which give to 

 the casts their characteristic appearance. 



2. "On the Dyeing Properties of Lichens," by Dr. W. Lauder 

 Lindsay. 



In this paper the author endeavours to direct public attention spe- 



