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Rubiaceae

Magee and Ahles (1999) noted a report of Canthium odoratum (G. Forst.) Seem. in MA but provided no details (e.g., location, source, validity of report). Specimens of this species from New England are unknown. Stenaria nigricans (Lam.) Terrel var. nigricans was reported from NH by Kartesz (1999), but the report was erroneous.

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Cephalanthus
1a. Plants woody; inflorescence a densely flowered, spherical cluster [Fig. 874]; corolla slender-funnelform
See list of 7 genera in 1b
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1b. Plants herbaceous; inflorescence not a spherical cluster; corolla salverform, rotate, cupuliform, or funnelform
- See list of 3 genera in 2a
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  2a. Leaves 2 at each node (i.e., opposite) [Figs. 882,883]; fruit fleshy or dehiscent; corolla pubescent on the adaxial (i.e., inside) surface (glabrous in Houstonia caerulea)
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    Mitchella
    3a. Flowers united by their hypanthia [Fig. 883]; fruit a berry; plants creeping, with evergreen leaves
  - See list of 2 genera in 3b
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    3b. Flowers separate, not united [Fig. 882]; fruit a capsule or schizocarp; plants prostrate to erect, sometimes tufted, with deciduous leaves
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      Diodia
      4a. Fruit a schizocarp, separating into 2 mericarps; ovules solitary in each locule; flowers borne in the axils of leaves; stipules terminated by a fringe of erect bristles
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      Houstonia
      4b. Fruit a capsule; ovules 4 or more in each locule; flowers borne at the apex of the stem, either solitary or in cymes; stipules entire, without a fringe
- See list of 4 genera in 2b
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  2b. Leaves 3–12 at a node (i.e., whorled; rarely only 2 leaves at some of the nodes in Galium) [Figs. 877,879]; fruit dry, schizocarpic, consisting of 2 indehiscent, 1-seeded carpels [Figs. 876,881]; corolla glabrous (pubescent on the abaxial surface in Galium circaezans)
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    Sherardia
    5a. Sepals triangular; corolla blue or pink, funnelform; inflorescence subtended by an involucre composed of a whorl of basally connate leaves
  - See list of 3 genera in 5b
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    5b. Sepals obsolete; corolla white, green-white, yellow, yellow-green, green-purple, or purple, or blue-purple in Asperula usually rotate; inflorescence not subtended by an involucre or subtended by one composed of distinct leaves
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      Rubia
      6a. Corolla 5-merous; fruit fleshy
    - See list of 2 genera in 6b
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      6b. Corolla 3- or 4-merous [Figs. 875,879]; fruit dry
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        Asperula
        7a. Corolla blue-purple, funnelform, with a prolonged, slender, basal, connate portion 4–5.5 mm long that is longer than the lobes; flowers with closely subtending, narrow bracteoles, borne on pedicels shorter than or as long as the ovary
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        Galium
        7b. Corolla various shades of white, yellow, or purple, rotate or cupuliform (funnelform in G. odoratum), the basal, connate portion up to ca. 1.5 mm long, shorter than or as long as the lobes; flowers without closely subtending bracteoles, often borne on pedicels longer than the ovary [Figs. 880,881]

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Show photos of: Each photo represents one genus in this family.