ALPINE PLANTS IN THEIR NATIVE HAUNTS. 



75 



adopt in the course of their adaptation to the alpine chmate/''' On 

 the one hand, he suggests that it exerts a protective influence on chloro- 

 phyll preventing its decomposition by excessive illumination, and, on 

 the other hand, he also regards it as probable that where it appears on 

 those parts of the vegetative organs which are less exposed to the light 

 its function is to absorb light and convert it into heat. As concerns 

 its protective influence on chlorophyll, he instances the two cases of the 

 Summer Savory (Satureia hoHensis) and the common flax {Linum 

 usitatissimum).-\ The former when growing in shady places is green, 

 but when grown in a situation fully exposed to the sun the foliage is 

 coloured d'ark violet by anthocyanin. The latter, on the other hand, 

 never develops anthocyanin, even though exposed to the full rays of the 

 sun. According to Keener, both plants require an equal temperature 



A B 



Fig. 51. — Oxeye Daisy, 



GROWN ON A MOUNTAIN (a) 

 AND AT SEA LEVEL (b), 

 DRAWN TO THE SAME SCALE. 



{After G. Bonnier.) 



B AO 



Fig. 52. — Jerusalem Artichoke grown at 

 AN altitude of 2400 M. (a), to compare 

 with the same species grown at sea 

 level (c), drawn to the same scale, 

 (b) is a plant from the mountain, less 

 reduced. {After G. Bonnier.) 



and an equally long vegetative period, but when cultivated in his experi- 

 mental Alpine garden on the Blaser the flax turned yellow, and died 

 without flowering, while the Summer Savory developed anthocyanin in 

 extraordinary abundance, flowered, and even produced ripe fruit capable 

 of germinating. Kecalling Bonnier 's laboratory experiments, it will be 

 remembered that the specimens of plants which he subjected to alter- 

 nating extremes- of temperature also developed anthocyanin where there 

 was no question of a high intensity of illumination. This, however, 

 does not necessarily invalidate Kerner's theories. On the contrary, it 

 may be taken to support the view that, in certain cases, by the develop- 

 ment of anthocyanin light is transformed into heat, and thereby com- 

 pensation is forthcoming for the loss of temperature in a plant's sur- 

 roundings. 



* See also Schroeter, O'p. cAt. pp. 646, 647. 

 t Kerner, of. cit. vol. i. p. 393. 



