ACUTA  Moran & C.H.Uhl, 1991

Distribution : Mexico (San Luis Potosi); moss-covered rocks, 1700 m, only known from the type locality.

Description (according to J. Thiede in IHSP, 2003) :

Herbs; roots thickened-fusiform, several, to 20 x 5 mm.

Stems erect.

Flowering branches 10 - 30 cm, only partly deciduous, base branched and woody-persistent, ≥ 15 x 0.5 cm.

Leaves spreading or somewhat curved downwards, subulate, acutely pointed, spurred, apically somewhat papillose, 10 – 20 x 1.5 - 3 mm.

Inflorescences dense spikes or thyrses, 3 - 10 cm, with 10 - 40 branches with 1 (-3) flowers, pedicels absent.

Flowers : Sepals ascending-spreading, lanceolate, acute, spurred, 3.5 - 4 x 1 mm, corolla pentagonal, 5 - 8 mm in diameter, petals 7 - 9 x 1.5 - 2 mm, white, tube 3.5 - 4 mm, lobes recurved, very acute, subapically aristate, 3.5 - 5 x 1.5 - 2 mm, uppermost ± 2 mm yellowish-green, filaments white.

Cytology : n = 16

Distinguished from all other species by the long corolla tube. Most closely related to V. diffusa and V. pringlei according to the protologue.