Dalea mollissima

  • Title

    Dalea mollissima

  • Authors

    Rupert C. Barneby

  • Scientific Name

    Dalea mollissima (Rydb.) Munz

  • Description

    6. Dalea mollissima (Rydberg) Munz

    (Plate XXXIII)

    Closely resembling D. mollis up to the inflorescence, on the average coarser, the vesture of the foliage more readily tarnishing when dry; stems 0.5-3.5 (5) dm long; leaf-spurs (0.5) 1-3 mm long; stipules subulate (1) 1.5-3 mm long; leaflets 4-7 pairs, 3-9 (10) mm long, the margins strongly undulate-crenate; racemes at full an- thesis and afterward (12) 13-16 (17) mm diam, the axis becoming 1.5-7.5 cm long; bracts 4.5-7 mm long, 1.1-1.6 mm wide; glands on pedicels 0.6-1 mm long, blackish- orange or black; calyx (5.8) 6.1-8.2 mm long, barbate with spiral hairs up to 1.5-2.2 mm long, the tube (2.5) 2.7-3.3 mm long, the intervals charged with one row of (3) 4-7 small orange glands, the teeth (3.1) 3.4-5.2 mm long; petals as in D. mollis except for the entire and glandless wing-tip; banner 2.8-3.7 mm long, the claw 1.3-2.1 mm, the blade (1.6) 1.8-2.2 mm long, (1.4) 1.7-2.2 mm wide; wings 2.4-3.1 mm long, the claw 0.6-1 mm, the oblong-ovate blade 1.8-2.2 mm long, 1.1-1.3 mm wide; keel 3.5-4 mm long, the claw 1-1.4 mm, the blades 2.6-2.9 mm long, 1.5-1.8 mm wide; androecium 4.3-5 mm, the anthers 0.4-0.5 mm long; 2n = 16 (Mosquin).— Collections: 81 (ii).

    Desert flats, washes, and outwash fans, sometimes on desert mosaic, mostly 0-750 (840) m (0- 2800 ft), in s. Nevada up to 1170 m (3900 ft), locally plentiful in years of good rainfall, s.-centr. and e. Mohave Desert, California, to Death Valley, the s. angle of Nevada, s. interruptedly through the Colorado Desert and the lower Colorado and Gila valleys in w. Arizona into the n.-e. corner of Baja California. — Flowering late January to May .—Representative: UNITED STATES. Nevada: Beatley 8387, 8625 (NY); Purpus 6029 (SD, UC); Kennedy (from Muddy R.) in 1906 (NY, UC). California: Twisselmann 11,948 (DAO, NY); Hall & Chandler 6999 (UC); Jones 3861 (NY, POM, UC); C. L. Hitchcock 5846 (NY, UC); Hitchcock & Muhlick 23,142 (NY); Jepson 12,534 (JEPS). Arizona: Maguire 15,500a (NY, UC); Gould & Macbride 4131 (NY, UC); Barkley & Reed 4236 (DAO, NY). MEXICO. Baja California: Wiggins & Wiggins 15,762 (DAO); Epling et al. (from Cucopah Mts.) in 1943 (F, NY, UC); Gander 2971 (SD). —To be expected in extreme n.-w. Sonora.

    Dalea mollissima (Rydb.) Munz, Aliso 4: 93. 1958, based on Parosela mollissima (very soft) Rydb., N. Amer. Fl. 24: 64. 1919. — "Type collected at Las Vegas Wash, [Clark County,] Nevada, April 22, 1905, Goodding 2237..." — Holotypus, NY! isotypi, GH, UC!— Dalea mollis var. mollissima (Rydb.) Munz, Man. S. Calif. 263. 1935. D. neo-mexicana ssp. mollissima (Rydb.) Wiggins, Contrib. Dudl. Herb. 3: 52. 1940.

    For comments on relationship, differential characters, and partly sympatric dispersal of D. mollissima and D. mollis, see discussion of the latter. For quick identification the broad bracts and undulate leaf-margin are the most easily observed features of D. mollissima. The species differs from D. neo-mexicana, to which Wiggins subordinated it as a subspecies, in its annual root, small banner, and particularly in its disjointing keel. It is true that the glandless wings of D. mollissima and D. neo-mexicana are similar, but Wiggins, in my opinion, overemphasized the significance of the likeness. In other respects, alike morphological and ecological, D. mollissima has more in common with D. mollis. See my definition of D. neo-mexicana, above.