POLYPETAL^— ROSACEA 



141 



the receptacle. Each one-chambered ovary (fig. 169, ov) contains 

 one ovule {o), and is surmounted by a single style {st), which 

 emerges through the mouth of the receptacular tube and 

 bears a simple stigma {sg). Fruit (fig. 170) compound, con- 

 sisting of numerous achenes concealed in the red hollowed 

 receptacle, which bears a persistent calyx. (Each achene is, of 

 course, developed from one of the separate carpels.) Seeds 

 having no endosperm. Dissemination. — The achenes are 

 scattered by the agency of birds, which peck at the red 

 receptacle and incidentally dislodge the achenes. The red 

 colour serves to render the fruit easily visible to birds. 



Type II. : STRAWBERRY (Fragaria vesca). 



The floral formula is the same as for the Rose, K5 C5 A 00 

 Goo. Beneath the calyx, and alternating with the sepals, is a 

 whorl of sepal-like members which forms an 

 epicalyx (fig. 82). The epicalyx represents, in this 

 case, the stipules of the sepals, which have joined 

 together in pairs. The shape of the receptacle 

 is curious (compare fig. 173, representing the 

 Blackberry flower), it is like a shallow saucer (re) 

 with a large lump irp) rising from its centre. " 



The sepals, petals, and stamens are attached to carpfiofStVaw- 

 the rim of the saucer, and are therefore perigynous. the' otSv^cuI 

 Numerous apocarpous carpels are inserted on the down the 

 central outgrowth. The disk {d) is like a ring, '"''^'^''• 

 and lines the space between the rim of the saucer and the 

 place of attachment of the central swelUng ; it excretes honey, 

 and is a nectary. Each carpel (fig. 

 171) has its style {sy) attached to 

 the side of the ovary {ov). The 

 ovary contains one ovule {p). Fruit 

 (fig. 172). — After pollination, the 

 central mass of the receptacle {re) 

 enlarges greatly, becomes first white 

 in colour, and finally changes into the 

 red, sweet, juicy "strawberry" which 

 we eat. Each carpel remains small 

 172.— Vertical section of and forms an achene {ae) with one 

 compound fruit of Strawberry, seed (j) inside it. The Complete fruit 

 of the Strawberry is compound, and consists of many achenes 



Fig. 



