ROSE FAMILY 409 



. . Leaflets densely pubescent beneath, if at all tomentose, the 



tomentum hidden under the long hairs, green and sparingly- 

 pubescent on the upper side. II. Nutt.^llt.'VNAe. 

 Leaflets principally tomentose beneath, only slightly hairy. 



V. Graciles. 

 Leaflets cleft more than half-way to the midrib into linear, oblong, 

 or lance-oblong divisions. 

 Stems ascending or decumbent at the base; stem-leaves few, 



reduced, with 3-5 leaflets. III. Candidae. 



Stems leafy; most of the stem-leaves 7-foliolate. 



IV. Pectinisectae. 

 Plants less than 2 dm. high. 



Leaves neither tomentose nor sUky, green. VII. Atjeeae. 



Leaves tomentose or silky, at least beneath. VIII. Concinnae. 

 Basal leaves digltately 5-foliolate, with an additional pair of smaller leaflets 

 on the petiole. VI. Subjugae. 



Basal leaves 3-foUolate. 



Leaves more or less tomentose beneath. IX. Ni\t:.\e. 



Leaves not tomentose. X. Frigidae. 



Leaves odd-pinnate. 



Style much longer than the mature achene, flliform. 



Leaves with 1-3 more or less approximate pairs of leaflets; plants low. 

 Leaves not at all tomentose. 



Style subterminal. VII. Aureae. 



Style attached below the apex of the achene. XI. Brevifoliae. 



Leaves more or less tomentose beneath. XII. Rubricaules. 



Leaves with 3-13 pairs of leaflets; plants usually comparatively tall. 

 Leaves grayish or whitish, silky or tomentose, at least beneath. 



XIII. Leucophyllae. 

 Leaves green on both sides or merely strlgose. XIV. Multijugae. 



Style not longer than the mature achene, tliickened and glandular below: leaves 

 usually more or less tomentose beneath. XV. Multifidae. 



I. SUPINAE. 



Achenes with a corky gibbosity on the upper suture; leaves all pinnate with 3-5 pairs of 



leaflets. 1. p. paradoxa. 



Achenes not gibbous. 



Lower leaves pinnate with 2 approximate pairs of leaflets, the upper ternate; stem 



strict; inflorescence cymose. 2. P. rivalis. 



Leaves all digitate; the basal ones rarely pinnate in P. monspeliensis. 

 Leaves ternate. 



Petals about half as long as the sepals; achenes whitish, smooth; hypanthium 

 in fruit 5 nam. wide or less. 

 Stem slender; petals cuneate or obovate; sepals and bractlets 3^ mm. long. 

 Stem -vvith diffuse, spreading branches; leaflets cuneate; mflorescence 



cjTtiose. 3. P. millegrana. 



Stem with erect or strongly ascending branches; inflorescence inclined 

 to be falsely racemose; leaflets broadly obovate; plant decidedly 

 glandular-puberulent. 4. P. biennis. 



Stem stout; petals obcordate; sepals and bractlets 5 mm. long; plants 

 densely glandular. 5. P. Kelseyi. 



Petals equalling the sepals or nearly so ; hypanthium in fruit about 7 mm. wide; 

 stamens 15-20. 6. P. monspeliensis. 



Lower leaves digitately 5-foliolate, or ternate with the lateral leaflets 2-cleft to 

 near the base; stamens 5. 7. P. pentandra. 



II. NUTTALLIANAE. 



Calyx and leaves more or less glandular-atomiferous ; whole plant yellowish or brownish 

 green: leaves with strong ribs. 

 Leaflets dissected into linear or oblong divisions. 8. P. brunnescens. 



Leaflets coarsely toothed with lanceolate teeth. 9. P. Nuttallii. 



Calyx and leaves not glandular-atomiferous; plant neither yellowish nor brownish; ribs 

 of the leaves not prominent. 

 Pubescence of the stem and petioles appressed. 

 Leaflets coarsely toothed. 



Leaflets obovate or oblanceolate, toothed to near the base. 



10. P. jiicunda. 

 Leaflets cuneate-obovate, the middle ones mostly toothed above the middle, 

 entire at the base. 31. P. glaucophylla. 



Leaflets dissected at least half-way to the midrib. 



Leaves rather densely silky beneath. 11. P. rectiformis. 



Leaves glabrous except the veins. 12. P. glabrata. 



Pubescence of the stem and petioles spreading; leaflets loosely hairy, often sUghtly 

 tomentose beneath. 13. P. dascia. 



III. Candid.\e. 



Segments of the leaflets lanceolate, acute; tomentum sparse. 22. P. viridescens. 



Segments of the leaflets oblong to linear, obtusish; tomentum dense. 

 Pubescence of the petioles and stems appressed. 



17* 



