The peculiarity of
Echinocereus waldeisii is that it forms only a single
out in the age, but not in the same extent as the similar species E.
tamaulipensis. The stems are clambering through the adjacent
vegetation and arise from a tuberous, dahlia-like root-stock.
Stem: Slender cylindrical, with pointed growing tips, dark
blue-green to purplish o brownish 60-120 cm long about 2 cm in diameter.
Ribs: Flat, without tubercles.
Central spine: One, pointed toward the stems tip, slightly
flattened, dark reddish, up to 10 mm long.
Radial spines: 8-16, thin, bristle-like, whitish or grayish, with
dark tips, up to 5mm long.
Flowers: Terminal or borne near the tips of older stems, narrowly
funnelform that often fail to open completely, up to 6cm long and 4 cm
Fruit: ovoid, dark green to brown, indehisent, with persistent
spines and wool.