334 BRITISH FLOWERING PLANTS chap. 



cas. Nous avons d'abord celui dans lequel les pieds sont 

 couches par le vent ou par une cause accidentelle de ce 

 genre ; on constate que dans Timmense majority des cas 

 sous Taction du geotropisme, les tiges s'^rigent avec une 

 grande rapidity et rattrapent ainsi en fort pen de temps 

 les dommages que leur a causes la tempete. Dans les 

 haies et les taillis, que les Galeopsis du groupe des 

 Tetrahit affectionnent, la sensibility phototropique fait 

 rapidement prendre aux tiges qui se courbent sur leurs 

 renflements une position favorable a 1' optimum d'^clai- 

 rage." 



Bbtonica 



Protandrous to homogamous bee flowers. 



B. officinalis (Wood Betony). — The corolla is 7 mm. 

 in length, and is not widened at the mouth, perhaps 

 because a tube of this length is accessible to all the 

 humble bees. 



Ballota 



Protandrous bee flowers. 



B. nigra.- — ^The corolla-tube has a length of about 7 

 mm., and is slightly widened at the mouth, so that the 

 nectar is accessible to a proboscis 6 mm. long. The 

 flower is protandrous, and if not carried away by 

 insects the pollen falls on to the lip of the corolla. 

 Finally the pistil elongates, and the stigma touches the 

 lip, taking up some of the pollen. The leaves are 

 hairy. 



Ajuga 



Nectar protected by a ring of hairs. The upper lip 

 of the corolla is very short, but the anthers and stigma 

 are protected by the bract of the flower above. There 

 are three British species. One, A. Chamcepitys, has 

 yellow flowers, with much-divided leaves ; the other two 

 blue or ash-coloured, with nearly entire leaves ; one, A. 

 reptans, is glabrous or nearly so, with creeping scions ; 

 the other, A. pyramidalis, very hairy, and without 

 creeping scions. 



