Xerophyte

Seeds

Black or brown, 1.3 long, 0.9 mm broad, pitted.

Description

Mammillaria sphaericaSN|11261]]SN|11278]], best known in culture as Dolichothele sphaericaSN|11280]]SN|11280]], is a small, light green sperical cactus, forming mounds or clumps to ca. 5 cm high and 5-30 cm in diameter, with 30-40 (or more) branches.

Taxonomy

Benson (1982) treated M. sphaerica as a variety of Mammillaria longimammaSN|11278]]SN|11261]], a species otherwise restricted to central Mexico and often segregated from Mammillaria as the genus Dolichothele (Bravo-Hollis and Sanchez-Mejorada, 1991). According to Weniger (1984) plants of M. sphaerica are readily distinguished from other mammillarias by their light green, almost yellow-green, stems.

Roots

Thick taproots, fleshy, to 2.5 cm thick, large in upper portion.

Note

The specific epithet alludes to the characteristic spherical stems.

Tubercles

Conical to mammiform-cylindrical, usually tapering toward apex, soft, turgid, spreading, flabby 12-25 long, 5-8 mm in diameter, when desiccated becoming much smaller, firm, and closely arranged at the base of the stem. Axils slightly short, woolly, without bristles.

Flowers

Broad, funnel-form, fragrant, brilliant lemon yellow, 4 long, 5-7 cm across. Outermost tepal margins entire (or minutely toothed near base). Inner tepals oblanceolate, bright yellow, paler near base, 20-30 mm long, 4.5-8 mm wide, acute or acuminate, the margins entire. Outer tepals with greenish-brown midregions and yellow margins. Filaments and anthers yellow, the stamens swirled around the yellow style. Stigma lobes eight, cream to pale yellow or greenish, 5-7 mm long.

Blooming Season

The plants bloom in spring and summer; fruiting May onwards.

Spines

13-15 per areole not obscuring the stem, smooth, whitish, yellowish, brownish, yellow to grey distally, glabrous. Radial spines 12-15 per areole, slender, grey, bristle-like, the longest (lateral and upper) ones 6-16 mm long, 0.1 mm in diameter, stiff. Central spines usually one per areole (reported 1-4), porrect, straight, not hooked or curved, similar to radial spines, 1-13 mm long, slightly thicker than radials (0.25 mm in diameter). Subcentral spines absent.

Stem

Spherical, depressed-spherical to dome-shaped, 4-5 tall, (2.5)5-6(-8) cm across, light green, almost yellow-green, soft, flaccid. Cortex and pith not mucilaginous. Latex absent.

Fruits

Greenish white, ultimately turning dull pinkish tan, reddish or maroon, ovoid to short cylindrical, 10-15 long, ca. 7 mm across, floral remnant weakly persistent. The fruits are juicy throughout, and have a pleasant aroma.

Areoles

Round, 1.5 mm in diameter.