Coryphantha tuberculosa
Coryphantha sulcata
cob cactus, white-column foxtail cactus
pineapple cactus
± diffuse.
diffuse or short taproots;
branches root adventitiously.
ovoid to cylindric (spheric), 4–16 × (2.2–)3–6(–6.5) cm;
tubercles (6–)8–11 × 3–6 mm, firm;
areolar glands absent;
parenchyma not mucilaginous;
druses in pith and cortex nearly microscopic, mostly spheric;
pith 1/8–1/4 of lesser stem diam.;
medullary vascular system absent.
spheric or obovoid, 4–8(–12) × 6–8 cm;
tubercles 8–19 × 10 mm, soft or flaccid (sagging in drought);
areolar glands seasonally conspicuous;
parenchyma not mucilaginous;
medullary vascular system absent.
(17–)21–41 per areole, ashy white, gray, or pale tan, tips of largest spines pinkish tan to reddish brown or reddish black, all straight;
radial spines 15–41 per areole, gray, (5–)7–12(–13.5) mm, largest spines 0.1–0.2 mm diam.;
subcentral spines 0–6 per areole;
central spines usually 5;
outer central spines (1–)3(–7) per areole, erect or ascending;
inner central spines (0–)2 per areole, porrect or descending, longest spines (5–)10–15(–18) × 0.2–0.3(–0.5) mm.
9–16(–18) per areole, yellowish or pinkish, later gray to nearly white with dark reddish brown or black tips, central spines often streaked or speckled with black on adaxial side;
radial spines 8–15 per areole, 9–16 mm, stout;
central spines 0–4 per areole, one porrect, others, if present, erect, sometimes appressed against radial spines, main central spine, when present, straight or curving downward, others straight, all terete or nearly so, longest spines 9–15 × 1 mm.
apical or nearly so, (18–)20–30(–32) × 20–45(–4) mm, sterile distal part of flower tube 5–8.5(–11) mm, longer than stamen-bearing part;
outer tepals conspicuously fringed;
inner tepals 21 per flower, pure white, pale rose-pink, or pale lavender-pink, darker centrally, midstripes ± inconspicuous, (9–)11–19 × 1.5–2.5(–3.5) mm;
outer filaments cream;
anthers pale yellow or nearly white;
stigma lobes 4–6(–8), white, (1.8–)2–4 mm.
apical or nearly so, 40–60 × 35–55 mm;
outer tepals entire;
inner tepals ca. 25 per flower, golden yellow (rarely greenish yellow), distally slightly darker, proximally bright red (rarely brownish red or greenish), 40 × 7 mm;
outer filaments bright red (rarely greenish in flowers without proximally red tepals);
anthers yellow;
stigma lobes 7–10, whitish or greenish yellow, ca. 3.5 mm.
bright red [green to maroon], ellipsoid, cylindric, or narrowly obovoid, (8–)13–25 × 3.5–6.5(–7.5) mm, not very succulent;
floral remnant strongly persistent.
usually green, becoming dull red, ellipsoid or oblong, becoming broadly ovoid, 15–25 × 10–15 mm, slimy;
floral remnant strongly persistent.
reddish brown, darker with age, obliquely obovoid, 0.9–1 mm, pitted.
dark reddish brown, somewhat comma-shaped, 2 mm, smooth, shiny.
= 22 (as C. strobiliformis, C. varicolor, and Escobaria tuberculosa).
= 22.
Coryphantha tuberculosa
Coryphantha sulcata
The names Coryphantha strobiliformis and Escobaria strobiliformis have been misapplied to C. tuberculosa by some recent authors (e.g., L. D. Benson 1982). Those names were based on Echinocactus strobiliformis Poselger, which is C. chihuahuensis (Britton & Rose) A. Berger.
Despite strong superficial similarity to other species in the genus, Coryphantha tuberculosa seems taxonomically isolated. Coryphantha tuberculosa superficially resembles C. sneedii, from which it is distinguished by (1) giant lenticular druses absent (abundant in older pith and cortex of C. sneedii); (2) fruits in region of sympatry always red (green in most U.S. populations of C. sneedii); (3) maximal expansion of flowers in late afternoon, sometimes remaining fully open at sunset (unlike any other species of Coryphantha); (4) flowers larger than those of C. sneedii, either pure white or a characteristic shade of pale lavender-pink, identifiable at a glance when flowers are alive and open; (5) anthers pale yellow, nearly white (bright yellow in C. sneedii); and (6) sterile distal part of receptacular tube longer than the stamen-bearing portion (short in C. sneedii).
On igneous and metamorphic substrates populations of Coryphantha tuberculosa mostly have unbranched stems. D. Weniger (1984) considered such populations to represent C. varicolor Tiegel; their reproductive structures, however, are identical to those of C. tuberculosa. Without seeds or flowers, mature specimens from such populations sometimes are indistinguishable from C. dasyacantha [hence the synonym C. dasyacantha var. varicolor (Tiegel) L. D. Benson].
Coryphantha tuberculosa is the type species of the segregate genus Escobaria, which includes the coryphanthas with pitted seeds.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
From Austin, Texas, eastward, Coryphantha sulcata has converged on the morphology of the sympatric C. missouriensis; the vegetative resemblance between these two species sometimes is nearly perfect, and numerous misidentifications occur in the literature. The porrect central spines of adult C. sulcata, when present, often curve downward, unlike the straight spines of C. missouriensis.
In the relatively arid western part of its range, Coryphantha sulcata converges on the vegetative appearance of C. echinus (usually unbranched, densely spine covered, with prominent central spines). In the general region of the Pecos River, where these two species approach each other geographically, identification of C. sulcata and C. echinus requires caution. Both species have strongly heter-omorphic growth, with central spines lacking until sexual maturity or later. The consistent interspecific differences are relatively subtle compared with the difference between age classes within populations of either species. The species are closely related, but not each other’s closest relative.
Coryphantha sulcata probably will prove conspecific with taxa in Mexico.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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