Ivesia kingii |
Rosaceae tribe Potentilleae |
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Ash Meadows ivesia, King's ivesia, King's mousetail |
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Habit | Plants usually grayish green to silvery, often glaucous; glands sparse. | Herbs, perennial, rarely annual or biennial, shrubs, or subshrubs; unarmed. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Stems | usually prostrate-decumbent to ascending, sometimes ± erect, 1–4(–5.5) dm. |
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Leaves | alternate, rarely opposite, pinnately (palmately) compound (simple in Alchemilla, Aphanes, and Chamaerhodos); stipules persistent (absent in Chamaerhodos), adnate to petiole; venation pinnate or palmate. |
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Basal leaves | 5–20 cm; sheathing base glabrous or densely strigose abaxially; stipules absent or linear to lanceolate, 1–4 mm; petiole 0.2–1.2 cm, hairs absent or sparse to dense, appressed or ascending, 0.5–2 mm; leaflets 15–60 per side, loosely to tightly overlapping, (1.8–)2–6(–8) mm, lobes (0–)2–4, narrowly oblanceolate to obovate, hairs absent or sparse to dense, ± appressed, 0.2–0.5(–1) mm. |
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Cauline leaves | 4–15. |
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Inflorescences | 5–100-flowered, 1–12 cm diam., flowers arranged individually and/or in few to several loose glomerules of 2–10 flowers. |
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Pedicels | (1–)2–20(–25) mm. |
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Flowers | 8–12 mm diam.; epicalyx bractlets lanceolate to elliptic or ovate, (0.8–)1–2(–2.5) mm; hypanthium shallowly cupulate, 0.5–2 × 1.5–4 mm, ± 1/2 as deep as wide; sepals sometimes purple-suffused, 2–4(–5) mm, narrowly acute to acuminate; petals white, spatulate or obovate to orbiculate, (2.8–)3–5(–6) mm; stamens 20, filaments filiform, 1.5–2.5 mm, anthers white to cream, 0.3–0.6 mm; carpels 2–9, styles 2–2.5(–3) mm. |
perianth and androecium perigynous; epicalyx bractlets present, sometimes absent; hypanthium usually patelliform, cupulate, or campanulate, sometimes turbinate, saucer-shaped, flat-bottomed, or subglobose to ellipsoid or ovoid; torus flat to conic or turbinate, enlarged (absent or reduced in Alchemilla, Aphanes, and Chamaerhodos); carpels 1–260, styles basal or lateral to subterminal, distinct; ovules 1(or 2), basal. |
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Fruits | aggregated achenes (achenes in Alchemilla and Aphanes); torus sometimes fleshy; styles deciduous or persistent, not elongate. |
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Achenes | light brown, 1.8–2.5 mm. |
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Ivesia kingii |
Rosaceae tribe Potentilleae |
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Distribution |
CA; NV; UT
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North America; Mexico; Central America; South America; West Indies; Bermuda; Eurasia; Africa; Atlantic Islands; Pacific Islands; Australia |
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Discussion | Varieties 2 (2 in the flora). Significant variation in habit, indument, leaflet lobing, and compactness of inflorescence can be found among and within populations of Ivesia kingii; no taxonomic structure has yet been discerned beyond the varieties recognized here. The variation within widespread var. kingii suggests that var. eremica resulted from a southward, late Pleistocene migration of a hairy phase of I. kingii with compact leaflets out of the Great Basin onto the northern edge of the Mojave Desert (J. L. Reveal 1980). Although densely hairy plants are encountered widely in the Great Basin, only in the Ash Meadows area of southernmost Nye County, the home of var. eremica, is there a consistently hairy phase. The leaflets of var. eremica are so tightly compacted that individual leaflets cannot be distinguished; in var. kingii, leaflets are individually distinct, though plants from Mineral County sometimes approach var. eremica in this regard. In the field, shoots of var. kingii arise directly from a taproot with the spreading branches flowing outwardly from a single point of attachment. In var. eremica, older, mature plants form compact mats with short, spreading caudex branches. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Genera 14–22, species ca. 860 (14 genera, 189 species, including 1 hybrid, in the flora area). The base chromosome number for Potentilleae is mostly x = 7 (8 in Alchemilla and Aphanes; 14 in Comarum). Variation in the number of genera recognized in Potentilleae is due to differences in generic delimitation between D. Potter et al. (2007) and the authors of Potentilla and segregates here (see 9. Ivesia and 8. Potentilla for discussion). In the former, Duchesnea, Horkelia, Horkeliella, and Ivesia are included within Potentilla. Likewise, Aphanes is included within Alchemilla by Potter et al. while it is kept distinct here. Potentilla and its segregates and Fragaria are host to Phragmidium rusts, but not the other genera of the tribe. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 9, p. 238. | FNA vol. 9, p. 119. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Unguiculatae | Rosaceae > subfam. Rosoideae | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Synonyms | Potentilla kingii | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Name authority | S. Watson: Botany (Fortieth Parallel), 91, 448. (1871) | Sweet: Brit. Fl. Gard. 2: sub plate 124. (1825) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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