150 ROSACE^E. (ROSE FAMILY.) 



ORDER 33. KOSACE^. (ROSE FAMILY.) 



Plants tvith regular flowers, numerous (rarely few) distinct stamens in- 

 serted on the calyx, and 1 - many pistils, which are quite distinct, or (in the 

 last tribe) united and combined with the calyx-tube. Seeds (anatropous) 

 I -few in each ovary, almost always without albumen. Embryo straight, 

 u-ilh large and thick cotyledons. Leaves alternate, with stipules, these some- 

 times caducous, rarely obsolete or wanting. Calyx of 5 or rarely 3-4- 

 8 sepals (the odd one superior), united at the base, often appearing double 

 by a row of bractlets outside. Petals as many as the sepals (rarely want- 

 ing), mostly imbricated in the bud, and inserted with the stamens on the 

 edge of a disk that lines the calyx-tube. Trees, shrubs, or herbs. A 

 large and important order, almost destitute of noxious qualities, and pro- 

 ducing the most valuable fruits. Very intimately connected with Legu- 

 minosae on one hand, and with Saxifragaceae on the other. 



I. Ovary superior and not enclosed in the calyx-tube at maturity. 



* Calyx deciduous, without bractlets ; pistil solitary, becoming a drupe. 



Tribe I. PRUNE.52. Trees or shrubs, with simple mostly serrate leaves. Ovules 2, 

 pendulous, but seed almost always solitary. Style terminal. 



1. Primus. Flowers perfect. Lobes of calyx and corolla 5. Stone of the drupe bony. 



* * Calyx mostly persistent ; pistils few to many (rarely solitary). 

 i- Calyx without bractlets ; ovules 2- many. 



Tribe II. SPIRJEE^E. Pistils mostly 5, becoming 2 -several-seeded follicles. Shrubs 

 or perennial herbs. 



a. Calyx short, 5-cleft. Petals obovate, equal 



2. Spiraea. Flowers perfect or direcious. Pods 1-valved. Herbs or shrubs ; leaves aim. 



pie or pinnate. 



3. Physocarpns. Pods inflated, 2-valved. Shrub: leaves palmately lobed. 



6. Calyx elongated, 5-toothed. Petals slender, unequal. 



4. Gilleiiia. Herbs ; leaves 3-foliolate. 



Tribe III. KlIBE^E. Pistils several or numerous, becoming drupelets in fruit. Ovules 

 2 and pendulous, but seed solitary. Perennials, herbaceous or with bieuuial soft-woody 

 steins. 



5. JC aim s. Pistils numerous, fleshy in fruit, crowded upon a spongy receptacle. 

 0. Dalibarda. Pistils 5 - 10, in the bottom of the calyx, nearly dry in fruit. 



*- Calyx-lobes mostly with bractlets; ovule solitary. 



Tribe IV. POTENTILLE./E. Pistils few -many, 1-ovuled, becoming dry achenes. 

 Herbs 



a. Styles persistent and elongated after anthesis, often plumose or jointed. 



7. Genm. Calyx-lobes usually with 5 alternating small braetlets. Stamens and carpels nu- 



merous styles becoming plumose or hairy tails, or naked and straight or jointed. 



b. Styles not elongated after anthesis, mostly deciduous. 



8. Waldsteinia. Petals and calyx-lobes 5 ; small or no bractlets. Stamens numerous. 



Acheues 2 - 6 ; styles deciduous from the base. 



9. Fragarla. Flower as in Potentilla. Receptacle much enlarged and pulpy in fruit. 



10. Potentilla. Petals 5 (rarely 4), conspicuous. Calyx-lobes as many, with an alternat- 



ing set of bractlets. Stamens and achenes numerous ; the latter heaped on a dry rs- 

 ceptacle. Styles commonly more or less lateral, deciduous or not enlarging in fruit. 



1 1 . Sibbalclia. Petals minute ; stamens and achenes 5 - 10 ; otherwise as Potentilla. 



