On the Rare Plant Technical Council List
Herbaceous perennial with a basal rosette of leaves and a scapose stem to 1.5 m tall; basal leaves linear, up to 1 m long, entire or rarely with one or two spinose teeth; cauline leaves few and reduced; inflorescence a compound umbel with compact hea...
Stems usually solitary, mostly 1-2 cm across by 1-2 cm tall, hemispherical but appearing conical due to spination; tubercles solitary with groove on upper side; spines 30-75 per areole, slender and bristle-like, spreading, to 10(22) mm long; flowers ...
Stems mostly solitary or sometimes up to 5 in a clump, globose to obovoid, the individual stems mostly 3-5 cm thick and 4-10 cm tall; tubercles on mature stems with upper surface grooved; spines about 50-60 per areole, spreading, typically white, of...
Escobaria orcuttii is distinguished by the relatively even and short length of the central spines, which seem to grade into the radial spines of similar length. This gives the plants something of a "groomed" appearance. Stems solitary, few in a cl...
Stems solitary, growing in clumps, or commonly branched to form small dense clusters, the individual stems mostly 2-4 cm thick and to 15 cm long; tubercles on mature stems with upper surface bearing a groove; spines with a yellowish cast often reddis...
Stems solitary, few in a clump, or commonly branched to form small dense clusters of 20 or more stems, the individual stems mostly 2-4 cm thick, to 15 cm tall; tubercles on mature stems with upper surface grooved; spines about 20-60 per areole, sprea...
Stems forming small dense clusters, the individual stems mostly 1-2 cm thick and to 8 cm tall; tubercles on mature stems with upper surface grooved; spines about 30-90 per areole, typically white often brown at tip, fading to gray, slender and bristl...
Stems growing in clumps, or commonly branched to form small dense clusters, the individual stems mostly 1-2 cm thick and to 10 cm tall; tubercles on mature stems with upper surface grooved; spines slender, spreading to erect in any one areole, mostly...
Stems solitary, growing in clumps, or commonly branched to form small dense clusters, the individual stems mostly 2-4 cm thick and to 15 cm long; tubercles on mature stems with upper surface bearing a groove; spines about 20-50 per areole, majority s...
Prostrate annual herb with several primary stems extending radially from a slender taproot; stems to 15 cm long, terete, strigulose with white recurved hairs 0.1-0.2 mm long, internodes 0.6-2.2 cm long; leaves opposite, stipules interpetiolar, separa...