4a. Echinocereus pectinatus (Scheidweiler) Engelmann var. wenigeri L. D. Benson, Cact. Succ. J. (Los Angeles). 40: 124, fig. 3. 1968.
Weniger’shedgehog,ashy white rainbow cactus, langtry rainbow cactus
Plants unbranched or few branched from near base in old age. Stems erect, short cylindric or sometimes spheric, 8-17(-25) × 5.6-8(-10) cm; ribs (13-)14-18, crests slightly undulate; areoles 4-15 mm apart. Spines (14-)17-26(-31) per areole, straight, tightly appressed (radial spines) or strongly projecting (central spines), presenting smooth general aspect to plant, ashy white, never pink, largest spines tipped purplish brown, annual growth increments not marked by rings of different color; radial spines (13-)15-24(-26) per areole, 7-10(-13) mm; central spines (1-)2-6(-7) per areole, short, inconspicuous, nearly terete, (2.2-)4-6 mm. Flowers 7-9(-11) × (5-)5.5-10(-13) cm; flower tube 10-15 × 15-25 mm; flower tube hairs 2-3(-5) mm; inner tepals often stiffly ascending, pink or magenta, white in proximal 1/2, green near base (distal colored portion varying greatly in extent), 34-62 × 7-19 mm, tips relatively thin and delicate; anthers yellow; nectar chamber 2-6 mm. Fruits dark purplish, 25-30 mm, pulp white to pink. 2n = 22.
Flowering Mar-May; fruiting May-Jul. Tamaulipan thorn scrub, degraded grasslands, often with Juniperus pinchotii, Chihuahuan desert scrub, limestone outcrops; 300-900[-1700] m; Tex.; Mexico (Coahuila).
Plants of Echinocereus pectinatus var. wenigeri are entirely whitish in aspect, without the conspicuous annual color banding characteristic of other "rainbow cacti" and without the gloss, luster, or translucency generally perceived in fresh spines. Without flowers or fruits, this variety is easily misidentified as E. reichenbachii, with which it sometimes grows sympatrically. Echinocereus pectinatus has white-centered flowers (with green throats, forming a target pattern) whereas E. dasyacanthus flowers, irrespective of color form, have only the greenish throats and no white bands on the inner tepals.