711 



Art. CLXV. — Varieties. 



350. Note on Linaria Cymhalaria. On the 28th of May, 1841, 

 my father called my attention to a curious circumstance respecting 

 the ivy-leaved toad-flax, or Aaron's beard {Linaria Cymhalaria). — 

 Having a plant in his study, dependant from a suspended flower-pot, 

 he observed that all the flowers invariably turned towards the win- 

 dow, which faced the south. Immediately after the blossoms had 

 fallen off", and the seeds began to perfect, the stems on which they 

 were placed gradually turned round away from the light, to the back 

 of the plant. Conjecturing the cause of this latter motion, he sup- 

 poses they revert for the purpose of depositing the seeds. In order 

 to understand this, we must recollect that the toad-flax is procumbent 

 and pendulous, growing on old walls in its native state. Consequent- 

 ly it is necessary that the inflorescence, which uniformly projects from 

 the wall, should after the fall of the corolla turn towards the back of 

 the plant, in order to deposit the seeds on the ^^■all, otherwise they 

 would fall to the ground and perish. — Robert Dick Duncan ; Vale 

 of Almond, Mid Calder, Edinbtirg It shire, June 10, 1843. 



[The experience of our readers will suggest many other examples of this pheno- 

 menon : the Cyclamen offers a curious and interesting instance; and the common pim- 

 pernel, being a trailing plant, is analogous to the case above mentioned. In Lindley's 

 ' Introduction to Botany ' in the chapter on " The Directions taken by the Organs of 

 Plants," is the following passage on this subject : — "The ovaria often take a different 

 direction after the fall of the corolla than they had before. Thus, during flowering, 

 the ovarium of Digitalis purpurea was nodding like the flower, the direction of which 

 it was compelled to follow. Immediately after the fall of the corolla, it turns upwards 

 towards the light, to which it is attracted by its green colour. A contraiy phenome- 

 non is presented by the ovarium of Convolvulus arveusis. The flower is turned to- 

 wards the .sky : as soon as it has foUen, the ovarium takes a direction towards the earth, 

 bending down the peduncle. This cannot be due to the weight of the ovarium, which 

 is much lighter than its peduncle, but must depend upon its disposition to avoid the 

 light, on account of its pallid hue, which is nearly the same as that of the root. In 

 Convolvulus sepium, on the contrary, in which the ovarium is equally pale, its erect 

 position is maintained, and the influence of decoloration counteracted by the greater 

 affinity to the light of two large green bracteae in which it is enveloped." — p. 286. — Ed.l 



351. Note on Cystopteris alpina at Low Layton. Having heard, 

 about four or five years ago, that this interesting fern — all trace of 

 which had been long obliterated by the reparation of the ancient wall 

 on which it once grew luxuriant and plentiful — had again made its 

 appearance in the original station, and that a specimen then recently 

 obtained from thence had been exhibited at one of the Linnean meet- 

 ings ; 1 was induced to extend my wanderings as i'ar as Low Layton 



