Geum macrophyllum |
Geum canadense |
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benoîte à grandes feuilles, bigleaf avens, large-leaf avens |
benoîte du Canada, white avens |
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Habit | Plants leafy-stemmed. | Plants leafy-stemmed. | ||||
Stems | 30–110 cm, puberulent and hirsute or sparsely hirsute. |
30–100 cm, glabrate to downy, hairs to 1.5 mm, sometimes glandular. |
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Leaves | basal 10–45 cm, blade interruptedly lyrate-pinnate, major leaflets 5–9, alternating with 4–15 minor ones, terminal leaflet usually much larger than major laterals; cauline 2–12 cm, stipules ± free, 7–23 × 3–12 mm, blade lyrate-pinnate, pinnate, 3-foliolate, or simple and 3-lobed. |
basal 10–25 cm, blade simple or pinnate, major leaflets 3–5, plus 0–4 minor basal ones, terminal leaflet larger than major laterals; cauline 3–8 cm, stipules ± free, 4–13 × 1–7 mm, blade 3-foliolate or simple and 3-lobed to unlobed. |
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Inflorescences | 3–16-flowered. |
3–15-flowered. |
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Pedicels | densely puberulent, sometimes with scattered longer hairs, sometimes stipitate-glandular. |
densely hairy, hairs of varying lengths, few long stiff ones, sometimes glandular. |
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Flowers | erect; epicalyx bractlets often absent, 0.5–2 mm; hypanthium green; sepals erect-spreading but soon reflexed, 2.5–5.5 mm; petals spreading, yellow, obovate, broadly elliptic, or suborbiculate, 3.5–7 mm, longer than sepals, apex rounded. |
erect; epicalyx bractlets 0.5–1.5 mm; hypanthium green; sepals spreading but soon reflexed, 3–6 mm; petals spreading, white, obovate to oblong, (3–)4–8 mm, ± equal to or slightly longer than sepals, apex rounded. |
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Fruiting tori | sessile or on less than 1 mm stipes, puberulent. |
sessile, densely bristly, hairs 1–2.3 mm. |
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Fruiting styles | geniculate-jointed, proximal segment persistent, 2.5–6 mm, apex hooked, sparsely to densely stipitate-glandular, distal segment deciduous, 1–2 mm, pilose in basal 1/3, hairs much longer than diam. of style. |
geniculate-jointed, proximal segment persistent, 2–8 mm, apex hooked, usually glabrous, sometimes sparsely hairy or stipitate-glandular, distal segment deciduous, 1–2 mm, pilose in basal 1/2, hairs much longer than diam. of style. |
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2n | = 42. |
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Geum macrophyllum |
Geum canadense |
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Phenology | Flowering spring–summer. | |||||
Habitat | Lowlands and upland forests, meadows, along streams, thickets, bottomland hardwoods, swamps | |||||
Elevation | 0–600 m (0–2000 ft) | |||||
Distribution |
AK; AZ; CA; CO; ID; MA; ME; MI; MN; MT; ND; NE; NH; NM; NV; NY; OR; SD; UT; VT; WA; WI; WY; AB; BC; MB; NB; NS; NT; NU; ON; PE; QC; SK; YT; Eurasia
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AL; AR; CT; DC; DE; GA; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NY; OH; OK; PA; RI; SC; SD; TN; TX; VA; VT; WI; WV; WY; MB; NB; NS; ON; PE; QC; Mexico (Chiapas)
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Discussion | Varieties 2 (2 in the flora). Characters useful in recognizing specimens of Geum macrophyllum are yellow petals, epicalyx bractlets often absent, proximal style segment sparsely to densely stipitate-glandular, and fruiting receptacles puberulent. Across its broad North American range from Alaska to California and Nova Scotia, G. macrophyllum exhibits considerable variation. Based largely on the shape of the terminal leaflet of the basal leaves and the degree of dissection and shape of the divisions of the distal cauline leaves, P. A. Rydberg (1913b) distinguished three species within the range of variation treated here as one species. Basal leaves of G. macrophyllum in the strict sense (var. macrophyllum in this treatment) have relatively large reniform to rounded terminal leaflets and the distal cauline leaves are three-cleft into rhombic or cuneate lobes. The basal-leaf terminal leaflets of G. perincisum (= var. perincisum) are only slightly larger than the laterals and are deeply lobed into rhombic-obovate segments; the distal cauline leaves are dissected into oblanceolate divisions. Both basal and cauline leaves of G. oregonense (= var. perincisum) are intermediate between those of G. macrophyllum and G. perincisum. W. Gajewski (1955) crossed all three taxa under discussion and examined leaf morphology and cytology of the F1 and F2 hybrids. He concluded that they were distinct but not yet completely separated species. Fairly well correlated with the more dissected leaves of G. oregonense and G. perincisum is the presence of minute stalked glands on the pedicels. The treatment here follows H. M. Raup (1931) in recognizing two varieties of G. macrophyllum based more on pedicel glandularity than leaf morphology. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Varieties and forms have been described in an effort to classify the variation encompassed in Geum canadense. In the eastern half of the United States, it is by far the most common, widespread, and variable of the Geum species. Nearly all writers of recent floras have not found it worthwhile to apply names to the variants. Perhaps the most distinctive and worthy of further consideration are plants from the southwestern corner of the range in Arkansas, Oklahoma, and Texas. These plants, some of which fit Fernald and Weatherby’s description of var. texanum, bloom from late March through May, significantly earlier than the rest of the species, which typically flowers after June first, even in the other southern states. Geum canadense hybridizes with G. urbanum (= G. ×catlingii J.-P. Bernard & R. Gauthier); see discussion under 15. G. urbanum. Geum album J. F. Gmelin is a superfluous name that pertains here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 9, p. 66. | FNA vol. 9, p. 68. | ||||
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Colurieae > Geum | Rosaceae > subfam. Rosoideae > tribe Colurieae > Geum | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | G. camporum, G. canadense var. brevipes, G. canadense var. camporum, G. canadense var. grimesii, G. canadense var. texanum | |||||
Name authority | Willdenow: Enum. Pl., 557. (1809) | Jacquin: Hort. Bot. Vindob. 2: 82, plate 175. 1772–1773 | ||||
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