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2 Pubescence of leaves and twigs stellate; stamens 10; [a cultivated exotic, rarely escaped]; [tribe Philadelpheae] | |
2 Pubescence of leaves and twigs simple; stamens 8-10 (Hydrangea) or 25-90 (Philadelphus); [natives and exotics]. | |
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4 Leaves not fleshy; inflorescence either a head or otherwise; [collectively widespread]. | |
6 Inflorescence otherwise; [more widespread]. | |
10 Leaves not fleshy; inflorescence otherwise; [collectively widespread]. | |
11 Leaves serrulate to serrate, the teeth uniformly around the margin or concentrated towards the tip; fruit dry, either indehiscent and 1-seeded or capsular and with several seeds. | |
12 Flowers 5-merous; petals fused; fruit indehiscent, 1-seeded; [montane, from e. TN, WV, and w. MD northwards in our area] | |
1 Leaves deciduous. | |
13 Leaves slightly to strongly fleshy; inflorescence a head, subtended by an involucre of phyllaries; [maritime situations] | |
13 Leaves not fleshy; inflorescence, flower, and fruit structure various, but not with the combination of features as above (sometimes the flowers in a head subtended by bracts, but then with other features differing, such as stamens 4, or green calyx present, or petals separate, or fruit a schizocarp of mericarps, etc.); [collectively widespread]. | |
14 Upright shrubs or trees, lacking any adaptations for climbing. | |
18 Leaves harshly scabrous on the upper surface; fruit a multiple of achenes; leaf venation pinnate but irregular | |
18 Leaves not scabrous; fruit a 2-4-seeded drupe; leaf venation neatly pinnate, the lateral veins nearly straight and parallel to one another | |
20 Leaves pinnate-veined; petals various, not both 4 and white (except sometimes in Hydrangea); stamens 1-15 (except 15-30 in Exochorda in ROSACEAE). | |
21 Inflorescence more diffuse, with internal axes and pedicels; flowers not both sympetalous and 4-lobed (except in Forsythia and Buddleja); fruit 1-seeded, 2-4-seeded, or 4-many-seeded. | |
26 Flowers 1-few, in axillary cymes; stamens 4-6; stems brown, tan, gray, or green. | |
27 Leaf venation neatly pinnate, the lateral veins nearly straight and parallel to one another; stems brown, tan, or gray | |
25 Petals fused, at least basally, and often strongly tubular; stamens 2, 4, or 5. | |
36 Fruit a drupe (1-4-seeded), fleshy at maturity. | |
40 Inflorescence a catkin, the flowers small (< 5 mm in diameter) and tightly arranged on the inflorescence axis (> 5 per cm of the axis) | |
40 Inflorescence various, but more diffuse, the flowers larger (> 5 mm in diameter, except for some flowers in Hydrangea in HYDRANGEACEAE) and loosely arranged (< 5 per cm of axis). | |
41 Capsule not angled. | |
45 Capsule about as long as wide, 3-6 mm long. | |