PLANTS: Annuals. STEMS: to 50 cm tall. LEAVES: to 10 cm long, sessile, narrowly elliptic to lanceolate or nearly linear; margins often entire, the lowest toothed to lobed, occasionally lobed throughout. BRACTS: narrowly lanceolate to ovate or obovate, with whitish bases, commonly on ovary; margins mostly entire or few-toothed on later flowers. FLOWERS: sessile or short-pedicellate; petals yellow, 2.5-10 mm long, 2-5 mm wide; staminodia 0; stamens ca. 10-30, all with linear filaments; style 1.5-7 mm long. CAPSULES: clavate to nearly cylindric, mostly tapering only near base; base not woody; body 10-16 (-20) mm long, when mature straight. SEEDS: pendulous, not winged, those in upper half of capsule grain-like, several-faceted, irregular in cross-section, the angles sharp; testa cells with straight adjoining walls, the surface walls pointed-papillate. 2n = 36. NOTES: Disturbed and open areas, from chaparral to pine woodlands (Map 4A): Apache, Cochise, Coconino, Mohave, Navajo, Pima, Santa Cruz, Yavapai cos; 900-2350 m (3000-7700 ft); Apr-Jun; CA, CO, NM, OR, TX, UT; n Mex. Best recognized by its erect, straight fruits that taper only near the base and its white-based bracts. The branches below the earliest flower are commonly alternate and less well-developed than those from lower nodes; most taxa in section Trachyphytum have mostly opposite and well-developed branches immediately subtending the earliest flower. This species generally looks like a less-robust version of M. veatchiana. It apparently intergrades in AZ with M. albicaulis and M. veatchiana. REFERENCES: Christy, Charlotte M. 1998. Loasaceae. J. Ariz. - Nev. Acad. Sci. 30(2): 96.