Mammillaria wrightii |
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biznaga de Wright, Wright's nipple cactus, Wright's pincushion cactus |
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Habit | Plants usually unbranched. | ||||
Roots | upper portion of primary root somewhat thickened and succulent proximally, otherwise fibrous. |
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Stems | flat-topped or spheric, 4–8 × 4–8 cm, ± flaccid; tubercles 6–24 mm; axils appearing naked; cortex and pith mucilaginous; latex absent. |
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Spines | 9–31(–34) per areole, white, usually tipped brown; radial spines 8–30 per areole, in 1 series, glabrous (puberulent in first year flowering plants); lateral spines bristlelike, 7–11 mm, stiff, longest and thickest of spines; adaxial spines often darker; central spines 1–4(–7) per areole, porrect or strongly projecting, 1 or all hooked, (5–)12–14(–21) mm; subcentral spines 0. |
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Flowers | 2.5–3.5(–5.2) × 2.2–4.5(–7.5) cm; outer tepal margins conspicuously fringed; inner tepals rose-pink or magenta [white], margins often paler; stigma lobes yellow or pale green (rarely reddish). |
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Fruits | green or dull purple, spheric to ovoid or obovoid, (9–)13–20(–28) × (6–)7–1.9(–26) mm, juicy throughout; floral remnant persistent. |
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Seeds | black, 1.3–1.5 mm, pitted; testa hard, anticlinal cell walls straight (not undulate); interstices conspicuously narrower than pit diameters; pits bowl-shaped. |
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2n | = 22. |
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Mammillaria wrightii |
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Distribution |
AZ; NM; TX; Mexico
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Discussion | Varieties 3 (2 in the flora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 4, p. 250. | ||||
Parent taxa | Cactaceae > subfam. Cactoideae > Mammillaria | ||||
Sibling taxa | |||||
Subordinate taxa | |||||
Name authority | Engelmann: Proc. Amer. Acad. Arts 3: 262. (1856) | ||||
Web links |