Mammillaria heyderi |
Mammillaria pottsii |
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biznaga China, Heyder's pincushion cactus, little nipple cactus |
fox-tail cactus, rat-tail nipple cactus |
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Habit | Plants unbranched, protruding relatively little above soil. | Plants usually branched. | ||||
Roots | obconic taproots; secondary roots diffuse. |
diffuse; upper portion not enlarged. |
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Stems | top-shaped, flat-topped (aerial part sometimes hemispheric in old age or in dense subtropical vegetation), protruding above ground 0–2 × (4–)7.5–15 cm, firm; tubercles 9–15(–20) × 3–7 mm; axils with short wool, bristles absent; cortex and pith not mucilaginous; latex abundant in healthy tissue throughout cortex of stem, tubercles, and sometimes flower receptacle, sticky, white. |
narrowly cylindric or clavate, 6–15(–30) × (1.5–)2–3.5(–4.5) cm, firm; tubercles 3–5 × 3–5 mm; axils with abundant, persistent, white wool, longest in flowering zone (where exceeding tubercle tips); cortex and pith not mucilaginous; latex absent. |
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Spines | (8–)10–18(–27) per areole, usually brownish, darker at tip, glabrous; radial spines (8–)10–22(–26) per areole, white to white-and-brown or brown, needlelike, 6–15(–16) mm, stiff, abaxial spines longest; central spines (0–)1(–4) per areole, porrect or ascending, not hooked, (0.5–)2–8 × 0.15–0.45 mm; subcentral spines 0. |
(33–)43–60 per areole, white to gray, tan, or pale reddish (central spines with darker, usually chalky blue tips), glabrous; radial spines (27–)37–49 per areole, white or pale tan, bristlelike, 3–6 × 0.05–0.1 mm, stiff, contrasting sharply with robust central spines; central spines 6–12 per areole, straight or weakly recurving throughout their lengths, not hooked, all ± projecting, abaxial and lateral central spines straighter and shorter, 5–8 mm, adaxial central spines 10–15 mm, all 0.2–0.3 mm diam. |
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Flowers | 1.9–3.8 × 1.5–3 cm; outermost tepal margins entire; inner tepals white, greenish or cream to pale pink, with tan, pink, greenish, or brownish midstripes, 11–19 × 2–2.5 mm; stigma lobes externally green, internally green or red (or pink), 2.5–3 mm. |
0.9–1.5 × 0.6–1.3 cm; outermost tepal margins toothed; inner tepals maroon-red to rusty red or reddish purple, with paler margins, 4 × 1.5 mm; stigma lobes dull pinkish white to reddish purple or orange-yellow, 1 mm. |
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Fruits | brilliant red: scarlet, carmine, or crimson, obovoid to clavate, 10–35(–40) × 5–8 mm, juicy only in fruit walls; floral remnant weakly persistent. |
bright red, cylindric-clavate, 15–20 mm, juicy only in fruit walls; floral remnant persistent. |
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Seeds | reddish brown, sometimes yellowish when fresh, 1–1.2 mm, deeply pitted; testa thin, relatively flexible; anticlinal cell walls sinuate, interstices narrower than pit diameters; pits cavernous or deeply concave. |
light to dark brown, 1–1.2 mm, pitted; testa hard; anticlinal cell walls deeply sinuate; interstices narrower than pit diameters; pits irregularly bowl-shaped. |
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2n | = 22. |
= 22. |
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Mammillaria heyderi |
Mammillaria pottsii |
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Phenology | Flowering (Feb–Mar, rarely later); fruiting Apr. | |||||
Habitat | Chihuahuan desert scrub with Agave lechuguilla and Larrea, gravelly flats, rocky slopes, on limestone or additional substrates | |||||
Elevation | 700-1300[-2100] m (2300-4300[-6900] ft) | |||||
Distribution |
AZ; NM; OK; TX; n Mexico
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TX; Mexico (Chihuahua, Coahuila, Durango, Nuevo León, Zacatecas) |
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Discussion | Varieties 2 (2 in the flora). Green fruits of Mammillaria heyderi with fully mature, viable seeds precede the ripe (elongate) fruits by six months to a year. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Mammillaria pottsii superficially resembles Coryphantha subgen. Escobaria: the erect cylindric stems are totally concealed by short, pale gray or ashy white spines. In M. pottsii, the ring of reproductive structures (flowers or fruits) encircles the stem two centimeters or more below the stem apex, unlike the apical flowers and fruits of most coryphanthas. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 4, p. 255. | FNA vol. 4, p. 255. | ||||
Parent taxa | Cactaceae > subfam. Cactoideae > Mammillaria | Cactaceae > subfam. Cactoideae > Mammillaria | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Name authority | Muehlenpfordt: Allg. Gartenzeitung 16: 20. (1848) | Scheer ex Salm-Dyck: Cact. Hort. Dyck. 1849, 104. (1850) | ||||
Web links |