CADUCUM R.T.Clausen, 1950

Distribution : Mexico (Tamaulipas); lime stone, 600m.

Description (according to IHSP, 2003) :

Perennial herbs branching from the base, with decumbent papillose stems.

Leaves alternate, rhombic-ovate, obtuse, papillate-crenulate, subterete, marginally densely covered with red spots, caducous, 7 - 22 x 4 - 12 mm, flowering branches erect.

Inflorescences few-flowered cymes, bracts oblong-elliptical, 2.5 – 4.5 mm, pedicels 1 - 1.5 mm.

Flowers 5-merous (rarely 6-merous), sepals broadly sessile, oblong, obtuse, subterete, 3.5 - 4.5 x ± 1 mm, suberect, petals basally connate, lanceolate, subacute, cucullate, ± 6 mm, white, first erect then spreading.

Cytology : 2n = 128, 192