The President's Address. By Lord Avebury. 297 



amplexicaule, L. hybridum, etc.)- No explanation of this has yet 

 been suggested. 



Many species have a ring of hairs in the throat. This would 

 tend to protect the nutlets when young and delicate, but its 

 principal use perhaps may be to prevent them from falling out, 

 unless thrown out by a high wind, which of course would increase 

 the distance to which they would be jerked. It is remarkable that 

 in the genus Calamintha, the ring of hairs is present in C. arvensis 

 and C. officinalis, but does not occur in C. Clinopodium. 



It would almost seem as if in some species — for instance, in 

 Mentha rotundifolia (Mint), Nepeta Cataria, and in Marjoram, 

 Origanum vulgare — the nutlets are intended to be dispersed in the 

 calyx, and in the latter species the bracts also appear to aid in the 

 dispersal. In Marrubium vulgare the calyx has ten spinous teeth, 

 one for each rib, recurved and strongly hooked at the tip. 

 Stachys sylvatica also has recurved teeth. In some species the 

 calyx teeth are covered with long, bristly hairs, which, besides their 

 usual function, may serve to assist the dispersal of the seeds. In 

 the Mint (Mentha sylvestris) the surface is covered with little 

 points and depressions, and in water absorb moisture, and swell up 

 into globular, transparent sacs. 



In Salvia Verbenaca, and other species of the genus, the nutlets 

 become mucilaginous when wetted. This perhaps may be useful 

 in causing them to adhere to damp ground. In S. pratensis the 

 nutlets when placed in water emit long colourless filaments, which 

 are more or less spirally coiled. In & Horminum the mucilaginous 

 tissue in places extends to half the depth of the whole, and as soon 

 as it comes in contact with water it swells out with great rapidity, 

 increasing to many times its original thickness. It develops into 

 thick threads, which move and, so to say, wriggle about like so 

 many worms. 



The Skull-cap (Scutellaria) is so called because the calyx bears 

 a curious resemblance to an ancient helmet, with the visor down. 

 The upper lip is closely pressed down on the lower one, thus pro- 

 tecting the nutlets. When ripe the top of the helmet flies off 

 at a touch, and the nutlets are at the same time jerked away. 



In Galeopsis versicolor the calyx has stiff glandular hairs, which 

 would cause it to be torn off if brushed against by animals. 

 The seeds are large and peculiar. It is now a weed of cultiva- 

 tion, but no doubt its peculiarities go back to a period before the 

 cultivation of corn (plate IV. fig. 5a). The nutlets are large, 

 oblong, bluntly trigonous in the lower half, strongly rounded or 

 convex on the upper half of the inner face, which slopes away to the 

 ridge forming the two lateral edges, convex on the dorsal aspect. 

 The surface is granular and dark brown, more or less densely 

 marked with grey specks. 



The nutlets of Ajvga are also peculiar. Those of Ajvga reptans 



