Plants annual, with minute, tuberous bodies; periderm absent. Stems 5-50 cm. Leaves: basal leaves in suberect to erect, seldom flattened rosettes, petiolate, 1-30 cm, blade often with weak red pigmentation, broadly rhombic to deltate or reniform, 1-7 × 0.5-5(-6) cm, apex obtuse to apiculate, mucro 1-3 mm; cauline leaves sessile, blade perfoliate or cleft or notched, 10 cm diam. or less. Inflorescences 1-bracteate; bract leaflike, 0.5-15 mm. Flowers 3-10 mm; sepals 1.5-4 mm; petals pink or white, 2-5 mm; ovules 3. Seeds 2-5 mm, shiny and smooth; elaiosome 1-3 mm. 2n = 12, 24, 36, 48, 60.

Annual herbs to 30 cm tall, spreading to erect. LEAVES: basal leaves several, narrowly oblanceolate to ovate to deltate or rhomboidal, 1.2 - 19 cm long, 0.3 – 4.5 cm wide, the base abruptly tapered; cauline leaves 2, connate, perfoliate, disk-like, subtending the inflorescence; apex 6 CANOTIA VOL. 2 apiculate or mucronate; margin entire or occasionally notched or cleft. INFLORESCENCE: a stalked or sessile raceme, dense or open, subtended by a single, often obscure bract. FLOWERS: 5-28; sepals 1.5-4.5 mm long, ovate; petals oblong, 1-3 mm long, pink or white, notched at tip. SEEDS: 1.0-1.8 mm long, brown to black. SYNONYMS: [Montia perfoliata (Donn ex Willd.) Howell]. NOTES: Moist areas, stream banks, or riparian areas in desert scrub to Ponderosa Pine/Gambel Oak habitat: Apache, Coconino, Gila, Graham, Maricopa, Mohave, Pima, Pinal, Yavapai cos.; 350-2200 m (1200-7300 ft); Feb-Jun; CA, CO, ID, MT, NV, OR, UT, WA, WY; British Columbia, Can. to C. Amer. Based upon annotated herbarium specimens and the recent Flora of North America treatment (Miller 2003), two subspecies of Claytonia perfoliata have been recognized in Arizona, subsp. intermontana and subsp. mexicana. They are not recognized as distinct entities here because the characteristics used to delimit these subspecies are not consistent or are extremely difficult to see. Subspecies intermontana is distinguished from subsp. mexicana by beet red or green herbage and gas pockets on the basal leaves (vs. green herbage only and no gas pockets). These subspecies have different geographical ranges (Chambers 1993, Miller 1978); subsp. intermontana grows in northwestern Arizona (Yavapai and Mohave Cos.), and subsp. mexicana grows in central to southern Arizona. It has been suggested that the subspecies of C. perfoliata may be difficult to identify due to environmental plasticity, genetic mixing among polyploids, and geographic overlap of distinct self-pollinating forms (Miller 1978).