RASPBERRY — BLACKBERRY 403 



is the edible part of a strawberry, the true fruit (ripened 

 gynaecium) being the achenes. 



In some cultivated varieties the flowers possess no stamens ; 

 neither the fruits proper nor their receptacles develop, unless 

 pollen is brought to them from others, hence the necessity of 

 planting kinds bearing staminate or bisexual flowers near them 

 in order to secure a crop of ' fruit ' of such varieties. 



6. The common Cinquefoils {Potentilla reptans L., and P. 

 Tormentilla Nesl.) and Silver Weed (Potentilla anserina L.) 

 are weeds belonging to the Rosaceae, with yellow flowers resem- 

 bling the strawberry in structure ; their receptacles, however, 

 do not become fleshy, and the fruit is a collection of closely 

 arranged achenes. 



To an unobservant eye the flowers of some of the Potentillas 

 resemble those of the buttercup species of Ranunadus : they are, 

 however, readily distinguished from the latter by the possession 

 of an epicalyx and a comparatively large receptacle. 



7. Belonging to the Rosacese is the genus Rubus, of which 

 the Raspberry {Rubus Idcsus L.) and Blackberry {Rubus fruti- 

 cosus L.) may be taken as types for study of the flowers and 

 fruit. The flowers of these plants generally resemble those of the 

 strawberry in structure : no epicalyx is present however, and each 

 carpel possesses two ovules instead of one. The flattened border 

 of the receptacle on which the petals and stamens are inserted is 

 broader in the raspberry and blackberry than in the strawberry, 

 but the central lump on which the carpels are placed is very 

 similar in all these flowers. 



After fertilisation the central portion of the receptacle, unlike 

 the strawberry, remains comparatively small, and does not become 

 succulent; the carpels, however, develop into small succulent 

 drupes, which are red or yellow in the raspberry and black or 

 deep purple in the blackberry. 



Thus the part which is eaten in the raspberry is a true fruit, 

 consisting of several one-seeded little drupes or drupels. 



