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Geum
See list of 10 species in this genusFresh petal color should be noted on herbarium collections because the color sometimes fades to a dingy yellow-white on old collections, regardless of the color in life. Petal length is an important character for identification. However, the petals do not reach a fully expanded size until the sepals are in a reflexed position for most species (i.e., measuring petal length while the sepals are ascending or merely spreading will result in a shorter measurement than is typical for the species). See Smedmark et al. (2003) for rationale of including Waldsteinia in Geum.
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1a. Flowering stems scapose or subscapose, with highly reduced stem leaves or lacking leaves altogether; styles ± straight, no portion conspicuously curved, not articulated or articulated at the base
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2a. Basal leaves with 3 leaflets, the lateral leaflets not or only somewhat smaller than the terminal leaflet; gynoecium with 2–6 (–10) carpels; styles deciduous at the base in fruit by an articulation point; petals 5–10 mm long
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2b. Basal leaves with 1 large terminal leaflet and 0–6 pairs of very small lateral leaflets; gynoecium with 30 or more carpels; styles persistent and plumose in fruit; petals 8–15 mm long
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1b. Flowering stems with evident, well-developed leaves; styles articulated near the middle, the basal part hooked at the tip and becoming indurate, the apical part usually deciduous
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3a. Epicalyx absent; cluster of achenes stipitate on a stalk 1–2 mm long, elevated above the persistent calyx; petals 1–2 mm long
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3b. Epicalyx present; cluster of achenes sessile or nearly so with respect to the calyx; petals 2–10 mm long
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5a. Petals yellow to orange-yellow
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6a. Basal segment of style minutely glandular [Fig. 844]; terminal segment of basal leaf blades suborbicular to reniform, truncate to cordate at the base, much larger than the lateral segments; pedicels minutely and densely puberulent, sometimes also with scattered, longer hairs; fruiting receptacle glabrous or inconspicuously short-pubescent, the carpel scars plainly visible on the denuded receptacle
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6b. Basal segment of style eglandular; terminal segment of basal leaf blades oblanceolate to obovate, cuneate at the base, not or scarcely larger than the lateral segments; pedicels both conspicuously hirsute and minutely puberulent [Fig. 842]; fruiting receptacle hirsute, the hairs partially obscuring the carpel scars on the denuded receptacle
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7a. Achenes usually numbering 200–250 per cluster, evidently spreading-pubescent near the base of the basal segment of style; petals (5–) 6–10 mm long; pedicels relatively stout, mostly thicker than 1 mm; stipules of stem leaves relatively small, conspicuously reduced compared with the leaflets; leaf teeth usually sharply pointed
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7b. Achenes usually numbering fewer than 100 per cluster, the basal segment of the style glabrous; petals 4–7 mm long; pedicels relatively slender, mostly thinner than 1 mm; stipules of stem leaves relatively large, ± appearing as a pair of leaflets set close to the stem; leaf teeth usually blunt to obtusely pointed
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5b. Petals white to yellow-white
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8a. Pedicels both conspicuously hirsute and minutely puberulent [Fig. 842], relatively stout, mostly thicker than 1 mm; basal leaf blades variable, but commonly with 3–7 principal leaflets (smaller leaflets also often present; sometimes with only 1 principal leaflet); achenes usually numbering more than 160 per cluster [Fig. 842]
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8b. Pedicels minutely and densely puberulent, sometimes also with scattered longer hairs [Fig. 843], relatively slender, mostly thinner than 1 mm; basal leaf blades with usually 3 principal leaflets; achenes usually numbering 30–160 per cluster [Fig. 843]
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9a. Petals ochroleucous, 2–4 mm long, much shorter than the sepals; leaf teeth usually blunt to obtusely pointed; stem moderately hirsute (at least in the basal half)
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9b. Petals white, (3.5–) 4–9 mm long, nearly as long as or longer than the sepals; leaf teeth sharply pointed; stem glabrous or sparsely hirsute near the base
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Each photo represents one species in this genus.