The President's Address. By Lord Avcbury. 275 



the facts fully before us. The diversity is astonishing, not 

 only in each large family, but even between nearly allied 

 species. 



Eanunculace^. — In the very first family, the Ranunculacere, 

 we find an example of these remarkable differences. There 

 are three main types. Some fruits are baccate, and adapted for 

 dispersal by animals, especially birds. Others are dry ; some are 

 several-, some one-seeded. The latter form achenes, the seed being 

 inclosed in the carpel. 



The many-seeded fruits or follicles burst at the ventral suture, 

 so that the seeds can fall, or be thrown out. 

 Our only baccate species is Actcea spicata. 



Two of our British Eanunculacea? — namely, Clematis Vitalba 

 and Anemone Pulsatilla — have long feathery persistent styles, 

 and are dispersed by the wind. It is remarkable that in the 

 genus Anemone some species have an elongated and persistent style, 

 while others have not. 



Species much exposed to the wind, those, for instance, living 

 in mountainous and open places, generally have feathery awns, 

 while in those preferring woods and meadows the awns are more 

 or less hooked. We find a somewhat similar division in the 

 Bosacere, Dryas having feathery, Geum rather hooked awns. 



The achenes are often wrinkled, netted or pitted, which would 

 make them lighter and more easily carried by wind. Others are 

 hairy, which would tend to the same result. Lastly, some are 

 hooked, as, for instance, several Ranunculi, especially a Continental 

 species, R. falcatus. 



When the fruit consists of a many-seeded follicle, the seeds are 

 liberated at maturity by the carpel opening at the top. The 

 stalk at the same time hardens, and, being elastic, the seeds are 

 jerked out by the wind, or sometimes by a passing animal. Such 

 seeds are generally smooth, and very often black. This arrange- 

 ment occurs in Caltha, Trollius, Aquilegia, Paionia, and other 

 genera. 



The seeds of Delphinium are curiously wrinkled, and in D. 

 Ajacis these form plaits of considerable depth, while in D. pere- 

 grinum they might be described as laminae, imbricated one over 

 another. The advantage of this arrangement is not clear to me. 

 Perhaps the reason is to make the seed lighter (plate IV. fig. 1). 



Berberide^e. — We have only one indigenous species, the com- 

 mon Barberry. The fruit is a berry ; the ovary is 1 -celled, and 

 contains a few basal, erect ovules, only one or two of which develop 

 into seeds. When there are two, they become plano-convex by 

 mutual pressure. They are thickest at the chalazal end, next the 

 apex of the fruit. 



As is usual in species where the fruits are intended to be eaten 

 by birds, the testa is crustaceous, and the surface almost smooth. 



D 2 



