n LABIATE 335 



A. reptans (Bugle). — The flower is generally homo- 

 gamous ; sometimes, however, the anthers open a little 

 before the stigma is ripe, while at others the reverse 

 happens. MacLeod, in Belgium, found a distinctly 

 protandrous form with large flowers. The stem is 

 alternately hairy on two faces, and glabrous on the 

 other two. In this species, as in many others, the 

 leaves are coloured red, especially on their under sides, 

 by anthocyanin. The use of the pigment seems to be 

 to turn the light- into heat-rays. The object of the 

 lower side being coloured is apparently that some of 

 the light would otherwise pass through the leaf and be 

 lost to the plant. It is found especially in plants 

 which grow in shady places, in Alpine plants, water 

 plants, and many sea-weeds, especially those found at 

 greater depths and not exposed at the ebb-tide. There 

 are other cases in which the anthocyanin is on the upper 

 surface. Here it probably serves as a screen, and pro- 

 tects the plants against too intense illumination by 

 turning part of the light into heat. This view seems 

 strongly supported by some of King's experiments. For 

 instance, he placed some chlorophyll in intense sunshine, 

 part, however, protected by a screen of anthocyanin 

 extracted from Beetroot. The part so sheltered remained 

 green, the rest was decomposed by the light. It is also 

 borne out by the frequent presence of the red colouring- 

 matter in young leaves in which the delicate epidermis 

 forms an inadequate protection from strong light. 



A. pyramidalis has the stem hairy all round, and 

 very hairy leaves. 



A. Chamsepitys. — The leaves are deeply divided into 

 three lobes. It is a southern form, and I have found it 

 on the Eiviera growing with Euphoi^hia Cyparissias, 

 which it so much resembled that I could not but think 

 it was a case of mimicry. The Euphorbia is protected 

 by its acrid sap, and the similarity may be a distinct 

 advantage to the present species, which itself has an 

 unpleasant taste. The leaves are rather viscous ; the 

 stem is hairy all round. 



