Proceedings of the Royal Society. 195 



per side of the tube, glabrous, bent nearly to a right angle immediately 

 below the stigma. Ovules very many. 

 This plant, though only lately introduced, is easily cultivated, either in the 

 open air or in the greenhouse, and has, with the Lophospermum eru- 

 bescejis, and the Rhodochiton voluUle, even, within a few months, given 

 a character to our trellises as new as that given a few years ago to our 

 greenhouses, by the introduction of the Fuchsias, Calceolarias, and the 

 varieties of the genus Salpi</lossis. 



Potentilla glabra. 



P. glabra ; caule fruticoso erecto ; ramis nutantibus ; foliis pinnatis, bi- 

 jugis, sursim ternatis vel simplicibus, utrinque glabris nitidis, subtus 

 glaucis (floribus albis.) 

 PotentUla glabra, Lodd. Bot. Cabinet, 914. 



Description Shrub erect, rigid, everywhere glabrous, excepting occa- 

 sionally on the edges of the leafets, on the young shoots, peduncles, and 

 outside of the calyx, where there are a few long spreading hairs. Flowering 

 branches cemuous. Leaves very numerous, small, pinnate, bijugous, 

 those towards the flowers ternate, or at the base of the peduncle simple ; 

 leaflets ovato-acute, turned forwards at their apices, reflected at their 

 sides, slightly undulate, veined, shining above, glaucous below, the up- 

 per pair slightly decurrent, and often united at their base to the termi- 

 nal leafet. Stipules dry and membranous, brown, 2-ribbed, united in 

 front of the petiole, and about as long as it, bifid at the apex. Peduncles 

 (about half an inch long) reflected upwards, collected in small numbers, 

 or solitary near the extremity of the branches. Petals subrotund, en- 

 tire, white, longer than the calyx. Stt/les short and abrupt. Receptacle 

 hairy. 



This is a very pretty little shrub, producing in abundance its small rose- 

 like white blossoms ; its erect rigid stem, and arched branches, forming 

 a neat round bush, and fitting it for cultivation along with the smaller 

 ornamental species of Cisttis. The flowers appeared in succession in the 

 open border at the Botanic Garden, Edinburgh, during August and Sep* 

 tember. The species is native of Siberia, and is stated by Mr Loddiges 

 to have been received by him from ]\Ir Busch of St Petersburgh in 

 1822. The difficulty of propagating it, noticed by Mr Loddiges, is 

 probably the reason why it is so seldom seen in collections. 



Proceedings of the Royal Society. 



1837, February 6. — Sir Thomas M. Brisbane, Bart. Pre- 

 sident, in the Chair. The following Communications were read : 



1. On the Action of Disintegrated Surfaces of Crystals upon 

 Light. By Sir D. Brewster. 



In this paper the author commences with a summary of the pre- 

 sent state of knowledge as to the internal constitution of crystalline 

 bodies ; and he then proceeds to describe the optical figures pro- 

 duced by the disintegrated surfaces of minerals and artificial mine- 

 rals, according as the disintegration is effected — 1. By the action of 

 solrents while the crystal is forming, or remains in the bowels of 

 the eartii ; 2. By the action of solvents on tlie surface of perfect 



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