556 PART IV. CLASSIFICATION. 



275 C). The stamens are usually indefinite, each whorl consisting of 

 as many or twice as many stamens as there are petals. These flowers 

 are distinguished from those of the Ranunculacese, which they somewhat 

 resemble, by the whorled arrangement of the stamens and by the 

 presence of the hollow receptacle; for in Ranunculaceous flowers the 

 stamens are arranged spirally and the sepals are quite free. 



Of the genus Potentilla, the fruit of which is an etserio of achenes on a 

 dry receptacle, many species are common, such as P. anserina, the Silver- 

 weed, reptans, Tormentilla, and others: the sub-genus Sibbaldia includes 

 the species P. procumbens, which is found on Scottish mountains : the 

 sub-genus Comarum includes the species P. Comarum, the Marsh Cinque- 

 foil. Fragaria is the Strawberry ; the receptacle becomes succulent as 

 the fruit ripens and bears the small achenes on its surface 5 F. vesca 

 and elatior are found in woods ; F. virginiana and other North American 

 species are cultivated. In the genus Rubus there is no epicalyx, the 

 ovary contains two ovules, and the fruit is an etserio of drupels ; Rubu* 

 Jd<xtis is the Raspberry ; its fruits separate from the dry receptacle when 

 they are ripe : in R. fruticosus, the Blackberry, and It. ceesius, the Dew- 

 berry, the upper part of the receptacle separates together with the fruits 

 when ripe. Dryas octopetala, the Mountain Avens (without epicalyx) 

 is a procumbent Alpine shrub with an oval long-tailed fruit (resembling 

 that of Clematis Vitalba). An epicalyx is present in most species of Geum ; 

 Geum urbanum and rivale (Avens) occur in woods and damp fields; the 

 long style is hooked. 



Tribe 6. Pamete. Ovaries five or fewer, contained in the cavity of the 

 receptacle, connate, and adnate to the wall of the receptacle (Fig. 367 D). 

 The spurious fruit is surmounted by the calyx. The individual fruits 

 either become hard and are like small drupes imbedded in the fleshy 

 receptacle, or they have only a thin wall, so that they are more like 

 capsules and seem to be loculi of the whole fruit, as in the apple for 

 instance, where the succulent portion is derived from the receptacle, and 

 the core consists of the fruits enclosing the seeds, which are basal, gener- 

 ally two in each carpel. Stamens indefinite : no epicalyx. Shrubs or 

 trees with deciduous stipules. 



I. With stony fruits. 



In the genus Cotoneaster, the fruits project above the receptacle : in 

 Cratsegus, the Hawthorn, they are completely enclosed ; C Oxijacantha, 

 the May, and its var. monogyna, the common White Thorn, are common : 

 Mespilus, the Medlar, has a large fruit which is surmounted by the five 

 large sepals. 



I. With coriaceous fruits. 



The genus Cydonia, the Quince, has numerous ovules on the ventral 

 suture of each carpel ; the outer layers of cells of the testa are mucila- 

 ginous. The genus Pyrus has two basal ovules : P. communis and others 

 are the Pear-trees ; the loculi of the spurious fruit, seen in transverse 

 section, are rounded towards the exterior ; the fruit is not hollowed at the 

 base : the sub-genus Malus includes P. Mains and others, the Apple-trees ; 

 the fruit is hollowed at the base, and the loculi, seen in transverse 



