ROSE FAMILY 401 



style nearly basal: oviiles ascending or nearly erect, orthotropous. 

 Stamens and pistils numerous; bractlets present; leaves piQ- 



nate. 18. Drithocallis. 



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



19. Ch.\ai.a.erhodos. 

 Style not articulate to the ovary; inflorescence spicate, racemose 

 or paniculate: hypanthium indurate, closely Investing the 

 achenes in fruit. 

 Hj-panthium not prickly; petals lacking. 



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

 lets toothed. 20. Sangxtisorba. 

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

 lets pectinate-pinnatifid. 21. Poteridium. 

 Hj-panthium prickly; petals present ; prickles of the hj'panthium 

 hooked. 22. Agremonia. 

 Disk at the mouth of the hj-panthium produced into a cylindric tube, 

 separa^ting 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. Waldsteinl\. 

 Styles partly or wholly persistent. 



Hypanthium hemispheric, campanulate or turbinate, persistent. 

 Pistils several or many. 



Flowers 8-10-merous; 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 conspicuously elongating in fruit, plumose 



below. 27. SlEVERSIA. 



Styles not much elongating in fruit, not plumose. 



28. ACOM.\,STYLIS. 



Sepals imbricate in bud; shrubs; leaves dissected into 

 narrow lobes. 

 Bractlets present; pistils numerous. 



29. Fallugla.. 

 Bractlets wanting; pistils few. 30. Cowania. 



Pistils usually solitary ; shrubs with 3-cleft leaves. 



31. PlTRSHIA. 



Hypantliium salver-shaped, the Umb deciduous; the tube persistent 

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

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



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

 with exfohating bark and simply digitately ribbed and lobed leaves. 

 Drupelets capped by a hard pubescent cushion; 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 compoxmd 

 and stem prickly or bristly. 35. Rubus. 



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



36. Rosa. 



1. OPULASTER Medic. Nine-bark. 



Shrubs with exfohating bark. Leaves alternate, 3-o-ribbed, more or less 

 lobed and usuallj' with more or less stellate hairs. Flowers in terminal corjanbs. 

 Hj'panthium 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 

 hypanthiimi. Pistils 1-5, more or less imited at the base; st^des filiform, ter- 

 minal; stigmas capitate; ovules 2-A. FoUicles 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 sterUe shoots scarcely longer 



than broad. 1. O. capitatus. 



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



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



2. O. cordatus. 

 Leaf-olades shallowly round-lobed, not cordate at the base, u.sually longer than 

 broad; eastern species. 3. O. intermedius. 



17 



