Xerophyte

Central Spines

Usually 1-2 (occasionally 3-4), whitish or pale brown to gray, erect or ascending, lacking hook, strongly flattened and thin, flexible, grooved, often twisted or curled, papery in texture, (12-)18-27(-38) mm long (to 4-5 cm long in cultivation), 0.4-2 mm wide. often obscuring the surface of the stem.

Description

The Grama Grass Cactus Sclerocactus papyracanthusSN|13716]]SN|13716]], best known as Toumeya papyracanthaSN|13720]]SN|13720]] is a tiny solitary cactus, rarely branched from the base in old age, with very characteristic flattened centrals spines resembling dried grass leaves or wood shavings. The main central spine, the longest and widest, is the lower central. The main central is flat, thin, flexible, curved, and often twisted.

Immature Specimens

Stems of young Sclerocactus papyracanthusSN|13716]]SN|13716]] are very slender, sometimes remaining less than 6 mm in diameter when 2-3 cm long. The spines of juveniles are similar to those in adults except that the central spines are relatively short.

Phenology

Blooming time April/May. The flowers opened relatively late in the after-noon, between 3

Roots

Fibrous 5-10 cm long.

Stem Anatomy

The stele is particularly thin, usually 2 mm or less in diameter, without medullary vascular system. Large mucilage cells occur in the tubercles and in the cortex, but are not present in the pith. Tissues which have mucilage cells are conspicuously slimy when freshly cut.

Flowers

On the new growth of the current season near the apex of the stem. Whitish, funnelform to narrowly bell-shaped, 18-25 mm long, ca. 1-2.5 cm wide. Inner perianth segments white with pale brown midstripes, largest ones about. 2 cm long, and 4 mm in diameter apex acute to mucronat. Outer perianth segments cuneate-spatulate, usually 9-20 lomg, with a green-purple to brownish central midstripe, and whitish margins, to 2 cm long, 3 mm wide. Filaments whitish to greenish yellow. Anthers cream-colored. Style greenish to cream-coloured, to 2 cm long. Stigma lobes 4-5, cream-coloured or pale green, 1.5 mm long. Pericarpel with or without scale bracts, spines also occasionally present in pericarpel areoles.

Stem

Dark green, cylindroid or slightly obconic, 2,5-7.5 ( or more) cm tall and 1-2(-4) cm in diameter. It has no ribs and tubercles are elongate, 1.5-5 mm long, dark grey-green, rather soft but usually is obscured by the spines;.

Radial Spines

Parallel to the stem surface, 6-9 per cluster, silvery-white to ashy-white, flexible, flattened, straight, appressed, about 2-5 mm long, 0.3-0.6 mm wide. The longest radials, to 5 mm, are the lowermost ones.

Fruits

Green, often changing to tan, spherical, 4.5-7 (or more) mm long, up to 4.5 mm wide dry and dehiscent at maturity along a dorsal slit and around the circumscissile apex; scales few or none, floral remnant persistent.

Areoles

1-2 mm in diameter at the summits of the tubercles, and generally 0.3 cm apart. Glands, which are homologous with spines, are pale reddish to tan, frequently on the adaxial sides of areoles which do not produce flowers. Areoles at the stem apex produce yellowish wool.