28 MOKPHOLOGICAL DISTRIBUTION OF ANTHOCYANINS [CH. n 



(c) The pigment develops in roots abnormally exposed. 



Exposed roots of Alnus (Mobius, 68). 



Roots of Salix grown in water in glasses (Schell, 287). 



Adventitious roots of Echeveria metallica (Pirotta, 42). 



Roots of Zea Mays growing in water or in moss and exposed to 

 light (Dufour, 305; Devaux, 308). 



Exposed roots of Saccharum qfficinarum (Benecke, 312). 



Adventitious roots above ground of Poa nemoralis (Beyerinck, 303). 



To Kerner (398) we owe the observation that rhizomes of Dentaria 

 bulbifera, Lathraea Squamaria and of species of Cardamine and Viola 

 become violet when exposed in water to sunlight. 



Gertz (19) lays stress upon the fact that numbers of roots and under- 

 ground stems form anthocyanin when, for some reason, they have been 

 exposed, as for instance when they grow out from banks of streams, 

 or in shallow water, or when exposed during autumnal ploughing. 

 He appends the following list of such cases including Tradescantia 

 zebrina, Eriophorum angustifolium, Phragmites communis, Rumex 

 Acetosella, Geranium molle, Potentilla anserina, Gunnera scabra, Stachys 

 palustris, Plantago major., Anthemis arvensis and Artemisia vulgaris. 



15. A development of anthocyanin appears to be characteristic 

 of many parasites and saprophytes, though possibly the absence of 

 chlorophyll has the effect of making the red pigment more conspicuous 

 (species of Cuscuta, Orobanche, Lathraea). Mirande (332) gives an 

 interesting account of the development of anthocyanin in the genus 

 Cuscuta. 



