ROSACEAE: Rose Family
KEY TO SPECIES OF ROSA IN GROUP D
KEY TO SE ROSA SPECIES
1. Leaf with 3 leaflets, rarely some with 5 ............................................................................................ 2
2. Leaves deciduous; stipules joined 7-15 mm with petiole; lateral leaflet stalk 0-0.5 mm ...............…. R. setigera
2. Leaves evergreen; stipules joined 2-5(7) mm with petiole; lateral leaflet stalk 2-5(7) mm …................ R. laevigata
1. Leaf with 5-11 leaflets, rarely some with 3 ........................................................................................ 3
3. Year 1 twigs finely and abundantly hairy .................................................................................. 4
4. Leaflets with teeth mostly 6-8 per cm. Stipules joined with petiole 2-5 mm .................................... R. bracteata
4. Leaflets with teeth mostly 4-6 per cm. Stipules joined with petiole up to 18 mm ...................... R. rugosa
3. Year 1 twigs glabrous or with scattered hairs (may have bristles, prickles, and/or stalked glands) 5
5. Leaves evergreen ............................................................................................................ 6
6. Teeth 25-30 on each edge of largest leaflet .............................................R. chinensis
6. Teeth (8)12-21(27) on each edge of largest leaflet ...................................................... 7
7. Leaflets dull above, apex mostly acute to short-acuminate, uncommonly to obtuse; marginal teeth on largest leaflet mostly 0.8-1.7 mm measured along edge toward leaflet apex ................................... R. multiflora
7. Leaflets shiny above, apex mostly obtuse; teeth on largest leaflet mostly 0.4-0.7 mm measured along edge toward leaflet apex ........................................................................................ R. wichuriana
5. Leaves deciduous ...................................................................... 8
8. Leaflet underside bearing scattered to abundant stalked glands (check with 40 X for stalks) ............ R. eglantaria
8. Leaflet underside without stalked glands except occasionally some on midvein .......... 9
9. Leaflets (5)7(9). Margin of stipules sharply toothed to cut into several very long narrow segments ......... R. multiflora
9. Leaflets (3)5-11(17). Margin of stipules entire to shallowly serrate (sometimes those of R. chinensis , and R. virginiana with 1-few linear teeth) ............................................................ 10
10. Year 1 twigs partly or totally bearing abundant mixed bristles and prickles, sometimes also with stalked glands ........................................................................... 11
11. Year 1 twigs with stalked glands mixed with prickles and bristles; stipules evenly narrow entire length ………. R. gallica
11. Year 1 twigs with only straight slender prickles and bristles; most stipules prominently widened toward apex ............................................................................... R. acicularis
10. Year 1 twigs with either bristles or prickles, rarely with neither or with both, bristles sparse ....................... 12
12. Prickles all needle-shaped, terete or some slightly flattened at base; straight or nearly so ............................... R. carolina
12. Prickles stout and little to much flattened at base, usually curved ..................................13
13. Central main teeth on each edge of the larger leaflets averaging 6-10 per cm, (0.8)1.2-1.7 mm across at base and 0.35-0.6(0.9) mm measured along edge toward leaflet apex; stipules not or scarcely widened toward apex, pairs jointly not appearing sagittate ............................................... R. palustris
13. Central main teeth on each edge of the larger leaflets averaging (3)4-6(7) per cm, (1.6)2-2.5 mm across at base, and (0.8)1-1.9 mm measured along edge toward leaflet apex; stipules definitely widened toward apex, often most pairs jointly appearing narrowly sagittate ............................................... 14
14. Leaflet margin mostly serrate, apical tooth obviously bigger than adjacent ones, 1.8-2.6 X 0.8-1.9 mm, most lanceolate. Stipules of main leaves usually glandular-toothed, sometimes a little dilated above. Opening in summit of hypanthium ca 4 mm across .................................... R. virginiana
14. Leaflet margin mostly serrate, apical tooth often not obviously bigger than adjacent ones, 1.1-1.8 X 0.8-1.1 mm; some bigger, if so, tooth with 1 to a few secondary teeth. Stipules of main leaves usually widened toward apex to 4 mm across. Opening in summit of hypanthium ca 1 mm across .................................... R. canina