319 



are firalariated, of others crenated ; and in one remarkable variety the 

 frond is much thickened, and the veins are more distant than usual, 

 " there being about one-third only of the usual number in a given 

 space." 



1840, February 13. Read, a Communication from the Rev. C. A. 

 Stevens, Kent, on Scrophularia aquatica of Linnaeus and of Ehrhart. 

 The author, considering the plants of the above authors to be distinct 

 species, has named the latter S. Ehrharti, and thus characterizes them. 



" S. aquatica, Linn. Leaves cordato-ovate, very obtuse, crenato-serrate, lower ones 

 auricula te; lateral cymes corymbose, many-(8 — 15)-flowerecl; sterile filament reni- 

 form, nearly round, entire ; capsule ovate, ratber acute. 



" Cymes mostly opposite ; peduncles and pedicels glandulose ; bracts generally li- 

 near, obtuse, entire. 



" S. Ehrharti, C. A. Stev. Leaves ovate or ovato-lanceolate, somewhat cordate at 

 the base, acute, serrate; lateral cymes divaricating, few-(5 — 6)-flowered; sterile fila- 

 ment bifid, its lobes divaricating ; capsule globose, very obtuse. 



" Cymes mostly alternate ; peduncles and pedicels hardly at all glandulose ; bracts 

 foliaceous, lanceolate, acute, serrate." — p. 57. 



There is also a reference to Mr. Stevens's paper on these plants in 

 'Ann. Nat. Hist.' v. 1. 



April 9. Dr. W. B. Clarke read a communication on certain pro- 

 perties existing in Tilia europaea, Linn. The author observes that 

 " this plant is remarkable for the immense quantity of mucilage con- 

 tained in the bark, and for the manner in which the cellular tissue in- 

 volving it is arranged w^ithin the meshes of the ligneous tissue." The 

 mucilage exists in a nearly solid form, but is soluble in water ; the 

 spaces in the woody fibre of the inner bark containing the cellular tis- 

 sue appear to be formed " by the cohesion of the woody tissue in cer- 

 tain parts, and its separation in others, to such an extent, that by the 

 gradual and lateral distension of the earlier layers of the liber in the 

 exogenous growth of the tree, certain spaces are made to intervene 

 between the reticulations of the woody fibre, which are gradually fill- 

 ed up by the development of cellular tissue." A transverse section of 

 a branch exhibits these spaces so disposed in the bark as to present 

 " a series of little conical figures, with their bases towards the circum- 

 ference of the bark, and their apices in communication with the me- 

 dullary rays, which traverse the wood of the stem." 



The author describes the mode of preparing this vegetable mucus 

 from the bark. 



