ROSE FAMILY 401 



Style nearly basal: ovxiles ascending or nearly erect, orthotropoiis. 

 " Stamens and pistils numerous; bractlets present; leaves pin- 

 nate. 18. Dkymocallis. 

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



19. Ch.\maerhodos. 

 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. S.\NGtTisoRBA. 

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

 lets pectinate-pinnatiftd. 21. POTERIDIITVI. 

 Hypantliium pricklv; petals present; prickles of the hj-panthlum 

 hooked. " 22. Aghimoma. 

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

 separatmg the stamens from the pistils; shrubs with opposite leaves 

 and branches. 23. Coleogyxe. 

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

 radicle inferior. 

 ^ Styles wholly deciduous. 24. Waldsteinia. 

 Styles partly or wholly persistent. 



Hypantliium hemispheric, campanulate or turbinate, persistent. 

 Pistils several or many. 



Flowers 8-10-merbus; low depressed imdershrubs 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 conspicuoiisly elongating in fruit, plumose 



below. 27. SlEVERSL\. 



Styles not much elongating in fruit, not plumose. 



28. ACOM.\.STYLIS. 



Sepals imbricate in bud; shrubs; leaves dissected into 

 narrow lobes. 

 Bractlets present; pistils niunerous. 



29. FALLTJGtA. 



Bractlets wanting; pistils few. 30. Cowania. 

 Pistils usually solitary ; shrubs with 3-oleft leaves. 



31. PURSHIA. 



Hypanthium salver-shaped, the limb deciduous; the tube persistent 

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

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



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

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

 Drupelets capped by a hard pubescent cusliion; styles glabrous. 



33. Rubacer. 

 Drupelets without cushion; 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. RUBUS. 



II. Carpels enclosed ia 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 

 lobed and usually with more or less stellate hairs. Flowers in terminal cor^-mbs. 

 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- 

 minal; stigmas capitate; Qvules 2-4. Follicles more or less inflated, opening 

 along both sutures; seeds obliquely 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 round-lobed, not cordate at the base, usually longer than 

 broad; eastern species. 3. O. intermedius. 



17 



