Stylocline sonorensis

Wiggins

Contr. Dudley Herb. 4: 26. 1950.

Common names: Sonoran or mesquite neststraw
Treatment appears in FNA Volume 19. Treatment on page 452. Mentioned on page 450, 451.

Plants 2–10(–15) cm. Leaves blunt (proximal) or acute (median and distal), mucronate, longest 6–13 mm; largest capitular leaves ± elliptic to narrowly ovate, 3–10 × 2–3 mm. Heads in cymiform to ± paniculiform, sometimes dichasiform arrays, ± spheric, largest 3.5–4.5 × 3–4 mm, thickly lanuginose. Phyllaries 0, vestigial, or falling, ± subulate, mostly 0.1–0.5 mm, unequal. Receptacles clavate, 1.2–2.2 mm, heights 2.8–3.5 times diams.; scars ± evenly distributed, mamillate. Pistillate paleae: longest 1.9–3.1 mm, winged distally; wings ± elliptic, widest in distal 1/3 of palea lengths; bodies (except midnerves) chartaceous; outermost paleae ± saccate. Functionally staminate florets 2–5; ovaries partially developed, 0.3–0.6 mm; corollas 0.9–1.4 mm. Cypselae 0.6–0.8 mm, slightly compressed; pappi: staminate of (1–)3–8 barbellate bristles 0.9–1.3 mm (proximal barbs longer, spreading).


Phenology: Flowering and fruiting Mar–May.
Habitat: Grassy hillsides, sandy drainages, with mesquite (Prosopis)
Elevation: 400–1400 m

Distribution

V19-748-distribution-map.gif

Ariz., Calif., Mexico (Sonora).

Discussion

Stylocline sonorensis is known from southeastern Arizona and northeastern Sonora. A disjunct, 1930 California occurrence was from apparently suitable habitat; recent searches have not relocated it.

Stylocline sonorensis is illustrated in J. D. Morefield (1992). It is superficially similar to S. citroleum; its closest relative is S. micropoides. Its ancestors may have been hybrid products involving Logfia depressa or its progenitors (Morefield).

Selected References

None.

Lower Taxa

None.