XXVI. ROSACES 137 



XXVI. ROSACES. THE ROSE FAMILY. 



Herbs, shrubs, or trees, with alternate leaves, mostly 

 toothed or divided, the stipules seldom wanting and often 

 leaf-like. Flowers in cymes, or solitary at the ends .of the 

 year's shoots, or more rarely in lateral bunches or racemes. 

 Sepals 4 or 5, united at the base into a lobed calyx, sometimes 

 double and usually enclosing the ovary or adhering to it. 

 Petals 4 or 5 or rarely none. Stamens usually indefinite in 

 number, inserted with the petals on the calyx below its lobes. 

 Ovary of 1, 2, or more carpels, usually distinct at. the time of 

 flowering, but sometimes combined even then into a single 

 5- celled ovary, which is then always inferior or combined with 

 the calyx. As the fruit enlarges, the carpels either remain free 

 or are variously combined with each other or with the calyx. 

 Seeds 1 or 2 (or in Spircea 3 or 4) in each carpel Embryo with 

 large cotyledons and no albumen. 



A numerous family, widely spread over the globe, but more in the 

 temperate and cooler parts of the northern hemisphere than within the 

 tropics. The indefinite stamens inserted on the calyx are sufficient to 

 distinguish the greater number of the genera from all other British 

 plants. In the few cases where the stamens are apparently definite, 

 there are no petals, but they then differ widely from all other apetalous 

 genera by their stipules and divided leaves, as well as by the structure 

 of the ovary. 



/"Ovary or ovaries superior~or free from the calyx, though sometimes enclosed 



1 



Ovary or ovaries inferior or adhering to the calyx-tube, which is closed over 



I .them 14 



A single ovary 3 



Several ovaries 4 



Trees, with a deciduous calyx and succulent fruit . . . .1. PRUNUS. 

 Herbs, with the calyx persisting round the dry seed-vessel .... 4 



No petals. (Herbs.) 5 



" t Four, five, or more petals. (Herbs or shrubs.) 8 



B J Leaves palmately lobed or digitate. Flowers in loose panicles or cymes . 6 



( Leaves pinnate. Flowers in heads 7 



fi f Calyx single, 4-lobed - . 8. ALCHEMILLA. 



\ Calyx double, 6 large and 6 small lobes . . . " POTENTILLA SIBBALDI. 

 ( Heads purplish. Flowers hermaphrodite, with 4 stamens t . 9. SANGUISORBA. 

 7 4 Heads green. Flowers dicecious, the males with numerous stamens. 



10. POTERIUM. 



a j Calyx-tube short and nearly flat, not enclosing the carpels .... 9 

 B \ Calyx-tube closing over the carpels or seeds ...'.... 14 



( Calyx single 10 



94 Calyx double, having as many external bracts as divisions, and alternating 



( with them "... 12 



Calyx-segments 6 . . . : '. 11 



Calyx-segments about 8. Carpels dry and distinct when ripe . . 3. DRYAS. 



Carpels dry, opening when ripe 2. SPIR^A. 



Carpels succulent, forming a kind of granulated berry ... 6, RUBUS. 



Carpels dry, ending in a long jointed awn 4. OKUM. 



Carpels without awna, small and leed-lika ... , j| 



