EXTEiCTS AND ABSTRACTS. 247 



Sachs found that some plants, if placed in complete darkness, develope 

 flowers of the normal colour and form, while in other cases a like 

 result is obtained if, while the flower-shoots are excluded from access 

 of light, the leaves are exposed to its influence. Sachs found, 

 however, that sometimes the latest flowers of an inflorescence are a 

 little afi"ected by darkness, e.g., those of a bright-red TropcEolum 

 majus appear yellowish, and much the same thing is seen in the 

 Wallflower and Phaseolus muUiJlorus, while the normally dark-red 

 flowers of Antirrhinum majus are white veined with red, with a 

 sulphur-coloured spot on the under-lip. 



Sorby, working with a dark form of the "Wallflower, found that by 

 diminishing illumination the rates of the colour-producing materials 

 are altered ; scarcely any erythrophyll, found in. great quantity under 

 normal conditions, is produced, and barely a third of the proper 

 amount of xanthophyll, while chlorophyll and lichnoxanthin are 

 present in regular proportion. 



The experiment of our author with Talipa Gesneriana confirmed 

 the result arrived at by Sachs, viz., that absence of light does not 

 influence the colouration of this plant. A number of bulbs of 

 this species grown in a cellar produced smaller flowers than ordi- 

 nary, which were not quite properly unfolded ; the scapes from these 

 bulbs also were remarkable by reason of the difterence in their 

 length, which was sometimes greater and sometimes less than 

 usual. 



Crocus vernus. — "Well-coloured flowers are formed in darkness, 

 while the perianth-tube and flower-axis are much lengthened. 



Hyaeinthus orientalis. — "W^orking with a dark violet-coloured 

 variety, Askenasy found, as did Sachs, that the presence of light 

 exerts considerable influence, in hastening by a fortnight the ap- 

 pearance of flowers. In addition it was found that the darkling 

 flowers were less deeply coloured than were those growing in daylight, 

 and a similar result was obtained with Scilla campanulata. 



A plant already bearing open flowers of Silene pendula was covered 

 over. The next unfolding flowers had petals of a paler colour, while 

 the latest ones were nearly white, in fact like the white variety, and 

 the red colour of the calyx which accompanies that of the corolla 

 and is absent from the white variety was fainter in plants grown in 

 darkness. Closely similar were the appearances presented by /*«/- 

 monaria officinalis. Antirrhinum majus, and Prunella grandijlora. 



It is found that the flowers of some plants, e.g., Tropccolum, Pha- 

 seolus, and Cucurhita do not develope further when the plants bearing 

 them are brought into darkness, whilst the vegetative organs grow 

 more vigorously under these conditions. Sachs holds that the dis- 

 position, vegetative or reproductive, which a plant assumes, depends 

 both on the quantity and quality of the nutriment it receives ; while 

 Askenasy supposes that in order to the perfection of flowers a simple 

 surplus of nourishment is required, and that when the amount of this 

 is insufiicieat it is entirely absorbed in the production of organs of 

 vegetation. 



"Without adopting either of these views, of which the validity or 

 otherwise would, we suspect, waver from species to species, we will 

 simply fxpress a hope that further experiments will be instituted on 



