ROSE FAMILY 401 



. Style nearly basal; oviiles ascending or nearly erect, orthotropous. 



Stamens and pistils numerous; bractlets present; leaves pin- 

 nate. 18. Drymocallts. 

 Stamens 5; bractlets wanting; leaves twice or thrice ternate. 



-. . . ■ 19. Chamaerhodos. 



style not articulate to the ovary; inflorescence spicate, racemose 



or paniculate; hypanthium indurate, closely investing the 

 achenes in fruit. 

 Hypanthium not prickly; petals lacking. 



Perennials, with rootstocks; stigmas muricate-papillose ; leaf- 



lets toothed. 20. Sanguisorba. 



Annuals or biennials, with taproots ; stigmas brush-like ; leaf- 

 lets pectinate-pinnatifid. 21. PoTERTDitTVf. 

 Hypanthium prickly; petals present ; prickles of the hypanthium 

 hooked. 22. Agrtmokia. 

 Disk at the mouth of the hypanthium produced into a cylindric tube, 

 separating the stamens from the pistils; shrubs with opposite leaves 

 and branches. 23. Coleogyne. 

 D. Seeds inserted at the proximal end of the ovary, i. e., perfectly basal; 



radicle inferior. 

 Styles wholly deciduous. 24. Waldsteixia. 



Styles partly or wholly persistent. 



Hypanthium hemispheric, campanulate or turbinate, persistent. 

 Pistils several or many. 



Flowers 8-10-merous; low depressed underslirubs with cren- 



ate or entire leaf-blades. 25. Dryas. 



Flower usually 5-merous. 



Sepals valvate: perennial herbs, with rootstocks: leaves 



pinnate; bractlets present. 

 Style conspicuously bent and distinctly geniculate 

 above, the upper hairy portion readily deciduous. 



26. Geum. 

 Style neither conspicuously bent nor distinctly geni- 

 culate, the upper glabrous portion persistent 

 or tardily deciduous. 

 Styles conspicuously elongating in fruit, plumose 



below. 27. SIEVERSIA. 



Styles not much elongating in fruit, not plumose. 



28. ACOMASTYLIS. 



Sepals imliricate in bud; shrubs; leaves dissected into 



narrow lobes. 

 Bractlets present; pistils numerous. 



29. Fallltgta. 

 Bractlets wanting; pistils few. 30. Cowania. 

 Pistils usually solitary ; shrubs with 3-cleft leaves. 



31. PURSHLV. 



Hj-panthiura salver-shaped, the limb deciduous; the tube persistent 

 and closely investing the fruit; shrubs. 32. Cercocarpus. 

 D. Fruits of more ot less fleshy drupelets; ovules 2, collateral. 



Styles club-shaped: stigmas slightly 2-Iobed; receptacle flat: unarmed shrubs 



with e.Kfoliating bark and simply digitately ribbed and lobed leaves. 

 Drupelets capped by a hard pubescent cushion; styles glabrous. 

 ' 33. Ruracer. 



Drupelets without ciisliion; styles hairy. 34. Oreobatus. 



Styles filiform, glabrous; stigmas capitate; receptacle convex, hemispheric or 

 nipple-shaped; drupelets without cushion; leaves in most species compound 

 and stem prickly or bristly. 35. Ritbus. 



II. Carpels enclosed in the hypanthium which becomes fleshy in fruit. 



36. Rosa. 



1. OPULASTER Medic. Nine-bark. 



Shrubs with exfoliating bark. Leaves alternate, 3-5-ribbed, more or less 

 ^bed and usually with more or less stellate hairs. Flowers in terminal cor^Tnbs. 

 Hypanthium hemispheric or nearly so. Sepals 5, persistent. Petals 5, white or 

 rarely pinkish, spreading. Stamens 20-40 on a disk, clothing the mouth of the 

 hypanthium. Pistils 1-5, more or less united at the base; styles filiform, ter- 

 mmal; stigmas capitate; ovules 2^. Follicles more or less inflated, opening 

 along both sutures; seeds obhquely pear-shaped, shining with a bony coat; endo- 

 sperm copious. [Physocarpus Maxim.] 



Carpels 3-5. united only at the base, turgid. 



Mature carpels glabrous, ovate, usually 5; leaves of the sterile shoots scarcely longer 



than broad. 1. O. capitatus. 



Mature carpels stellate, short-ellipsoid, abruptly acute, usually 3 or 4. 



Leaf-blades deeply lobed, as broad as long, cordate at the base; western species. 



2. O. cordatus. 

 Leaf-blades shallowly roimd-lobed, not cordate at the base, usually longer than 

 broad ; eastern species. 3. O. intermedius, 



17 



