ROSE FAMILY 401 



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

 Stamens and pistils numerous; bractlets present; leaves pin- 

 nate. 18. DRYMOCALLIS. 

 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. POTERIDITTM. 

 Hypanthium prickly; petals present ; prickles of the hypanthium 



hooked. 22. AGRIMONIA. 



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. 



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. 



Hypanthium hemispheric, campanulate or turbinate, persistent. 

 Pistils several or many. 



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



ate or entire leaf-blades. 25. DRYAS. 



Flower usually 5-merous. 



Sepals yalvate; 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 imbricate in bud; shrubs; leaves dissected into 



narrow lobes. 

 Bractlets present; pistils numerous. 



29. FALLUGIA. 

 Bractlets wanting; pistils few. 30. COWANIA. 



Pistils usually solitary ; shrubs with 3-cleft leaves. 



31. PURSHIA. 

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



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

 D. Fruits of more 01 less fleshy drupelets; ovules 2, collateral. 



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



with exfoliating 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 compound 

 and stem prickly or bristly. 35. RUBUS. 



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 

 lobed and usually with more or less stellate hairs. Flowers in terminal corymbs. 

 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; ovules 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 



