Dalea versicolor var. sessilis
Rupert C. Barneby
132d. Dalea versicolor Zuccarini var. sessilis (Gray) Barneby
(Plate CXIX)
Stems 1-several, mostly 2-7 dm long, suffruticulose or sometimes truly shrubby, in fall few-branched distally, each branch terminating in a relatively long spike, in spring floriferous serially along the old stems from axillary short-shoots; stipules 1-3 mm long; foliage always more or less pilosulous or puberulent, the primary leaves often less densely so than the secondary ones; leaflets of primary leaves 4-9 pairs, oblanceolate to elliptic or obovate, mostly obtuse or retuse, usually not strongly carinate; spikes 12-15 mm diam, the axis 0.5-2 cm long; calyx 5.7-7 mm, the tube 2.4-2.8 (3) mm, the dorsal tooth 3-4 mm long; epistemonous petals rose-pink or -purple, the keel-blades often paler in outer half; n = 7 II (Spellenberg, 1973). —Collections 32 (i).
Rocky hillsides and boulder-strewn canyon benches, in grama grassland and open oak woodland, 900-2100 m (3000-7000 ft), locally abundant around the periphery of the Gila basin in s.-e. Arizona (s. Pinal, Graham, s. Greenlee, Pima, Cochise, and Santa Cruz counties), s. along the w. slope of Sierra Madre to the upper Rio Papa- gochic in Chihuahua, and through the hill-country of n.-e. Sonora as far as Sierra de Charuco on the Chihuahua-Sonora border in lat. 30° N. — Flowering late August to November, and again abundantly in April and May.—Representative: UNITED STATES. Arizona: Gentry 5972 (UC); A. & R. Nelson 1542 (NY); Maguire 10,964 (NY, UC), 11,502 (NY); Blumer 1477 (UC, L, W). MEXICO. Sonora: Wiggins 11,677 (MEXU, MICH, SD, TEX, US); Gentry 8015 (MEXU, UC), 8056 (MEXU, UC). Chihuahua: Hartman 634 (NY); Tucker 2519 (UC); Correll & Johnston 21,617 (RENNER).
Dalea versicolor Zucc. subsp. versicolor var. sessilis (Gray) Barneby, Phytologia 26: 1. 1973, based on D. wislizeni var. sessilis (stemless, of the lateral drought-inhibited vernal inflorescence) Gray, Proc. Amer. Acad. 16: 105. 1880.— "New Mexico and Arizona, Greene, 1887, Lemmon 1880." — Lectotypus, Greene 1070, collected in foothills of Chi- ricahua Mts., 2 Apr 1877, GH! — Parosela wislizeni var. sessilis (Gray) Vail, Bull. Torrey Club 24: 15. 1897. P. sessilis (Gray) Rydb., N. Amer. Fl. 24: 104. 1920. Dalea sessilis (Gray) Tidest. in Tidest. & Kitt., Fl. Ariz. New Mex. 183. 1941. D. wislizeni subsp. sessilis (Gray) Gentry, Madrono 10: 246, pi. 23, fig. 3. 1950.
Parosela sanctae-crucis (of Santa Cruz, Sonora) Rydb., N. Amer. Fl. 24: 103. 1920 ("Sanctae-Crucis"), based on Dalea wislizeni var. foliolis minus sericeis etc. Gray, Pl. Wright. 2: 38. 1853. — "Mountain ravines near Santa Cruz, Sonora, Sept. ([C. Wright] 986)." — Holotypus, GH! isotypi, NY, UC. —Parosela wislizeni var. sanctae-crucis (Rydb.) Macbr., Contrib. Gray Herb., New Ser. 65: 19. 1922. Dalea wislizeni var. sanctae-crucis (Rydb.) Kearn. & Peeb. Jour. Wash. Acad. Sci. 29: 484. 1939.
The concept of a seasonally dimorphic var. sessilis worked out (as D. wislizeni subsp.) by Gentry (1950, p. 246, pl. 23) is adopted here without reservation. Its autumnal form (P. sanctae-crucis), with leafy virgate stems branched distally into a panicle of spikes, resembles in habit the equivalent seasonal aspect of var. glabrescens (subsp. wislizeni Gentry, 1950, p. 240, pl. 20) but may be distinguished, as pointed out by Gentry, by less prominently keeled, flatter, more obtuse leaflets, and even more reliably by the confluence of the green margins of the rachis under each pair of petiolules. The showy spring form of var. sessilis, in which the stems are clad in place of primary leaves, now fallen, with a succession of subsessile heads representing axillary short-shoots, resembles the seasonal equivalent of var. calcarata very closely. They have essentially the same type of leaflet and can hardly be told apart except in the autumnal stage, of which the primary cauline leaves have significantly more numerous leaflets.
In the protologue Gray mistakenly attributed var. sessilis to New Mexico as well as Arizona, from which state all his material originated. I have seen no evidence that it occurs in New Mexico, but it is nevertheless to be expected in the mountains of the southwest corner. Gentry (1950, fig. 3) has no New Mexican station on his distribution map.
References: [Article] Barneby, Rupert C. 1977. Daleae Imagines, an illustrated revision of Errazurizia Philippi, Psorothamnus Rydberg, Marine Liebmann, and Dalea Lucanus emen. Barneby, including all species of Leguminosae tribe Amorpheae Borissova ever referred to Dalea. Mem. New York Bot. Gard. 27: 1-892.Multimedia:
