II ROSACE.-E 181 



S. officinale (Great Burnet). — Honey is secreted as 

 usual. The four lobes of the calyx are deeply coloured 

 a rich dark brown. The florets are small, but 50 to 

 100 are united in an oval or cylindrical head. They 

 expand from below upwards, only one ring being open 

 at once, and are richly visited by insects, especially 

 flies and butterflies. 



POTERIUM 



P. Sanguisorba (Salad Burnet), on the other hand, 

 has no honey. The flower-heads are greenish, smaller 

 and more globular. The florets are female at the 

 summit, complete in the centre, and male below. The 

 stamens are more numerous, and the pollen is carried by 

 wind, the anthers being exserted on long, slender, 

 pendulous filaments, which are white, yellowish, or red 

 in colour. The anthers are yellow or red. The stigmas 

 are numerous and elongated, so as more effectively 

 to catch the grains of pollen. This is mainly a wind- 

 flower ; still the flowers are occasionally visited by flies, 

 solitary wasps, and a few other insects. 



The achenes are enclosed in a hollow development 

 of the receptacle, often termed the " calyx tube." There 

 is generally a single achene, but sometimes there are 

 three. It or they fill the receptacle, so that where three 

 are present they are more or less triangular. Each achene 

 contains a single seed. The receptacle is winged, and 

 no doubt serves for the dissemination of the seeds. 



Agrimonia 



A. Eupatoria (Agrimony). — There is a fleshy ring 

 at the base of the pistil which has all the appearance 

 of a nectary, but the presence of honey has not been 

 observed. The flowers open very early in the morn- 

 ing. The " calyx tube " is persistent, and is covered 

 with exquisite little hooks, which fix themselves into 

 the hair of any passing animal or into clothes, and 

 thus ensure the dispersal of the seeds. The flower 

 lasts three days. At first the stigmas are ripe, but 



