| 1. Leaves evergreen (but see V. parvifolium), leathery, veins not prominent on lower side; pedicels jointed to flower; filaments ± hairy |
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| 2. Plant 530 dm, branches stout; leaf > 20 mm, serrate; corolla lobes < tube, erect to spreading when anthers open |
| V. ovatum |
| 2' Plant < 1.5 dm, branches slender; leaf generally 717 mm, ± entire; corolla lobes >> tube, reflexed when anthers open |
| V. macrocarpon |
| 1' Leaves deciduous, thin or ± thickened, veins generally prominent on lower side; pedicels not jointed to flower; filaments glabrous |
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| 3. Leaf entire; calyx lobes generally > tube, persistent; twigs not angled, not green; flowers solitary or few on leafless older shoots |
| V. uliginosum subsp. occidentale |
| 3' Leaf serrate or minutely so (but see V. parvifolium); calyx lobes ± 0 or generally < tube, deciduous; twigs angled or not, green or not; flowers often solitary in axils of lowest leaves of youngest shoots |
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| 4. Twigs strongly angled, green; fruit red (or dark purple when dry) |
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| 5. Shrubby shrub, < 5 dm, rhizomed; leaf serrate, lower surface glabrous |
| V. scoparium |
| 5' Erect shrub, > 5 dm, not rhizomed; leaf entire to serrate or with only a deciduous, sharp point at tip, lower surface, especially midvein, puberulent |
| V. parvifolium |
| 4' Twigs not or weakly angled, not green but sometimes greenish or yellowish green; fruit not red (but see V. membranaceum) |
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| 6. Plant generally 515 dm; twigs weakly angled; leaf generally ovate to elliptic or obovate, 25 cm, very thin, membranous, often rounded to truncate at base, acute at tip |
| V. membranaceum |
| 6' Plant generally < 5 dm; twigs not or weakly angled; leaf generally oblong or obovate to oblanceolate, rarely elliptic, generally 13.5 cm, generally thin but not membranous, tapered at base, seldom acute at tip |
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| 7. Youngest twigs generally puberulent or glandular; leaf not glaucous, generally oblong or obovate to elliptic; corolla narrowly urn-shaped; fruit < 9 mm wide |
| V. caespitosum |
| 7' Youngest twigs generally glabrous, glaucous; leaf glaucous, obovate or oblanceolate, rarely elliptic; corolla ± spheric; fruit > 9 mm wide |
| V. deliciosum
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