Mentzelia jonesii

(Urban & Gilg) H. J. Thompson & J. E. Roberts

Phytologia 21: 282. 1971.

Common names: Jones’s blazingstar
Endemic
Basionym: Mentzelia albicaulis var. jonesii Urban & Gilg Nova Acta Acad. Caes. Leop.-Carol. German. Nat. Cur. 76: 29. 1900
Synonyms: M. californica H. J. Thompson & J. E. Roberts M. nitens var. jonesii (Urban & Gilg) J. Darlington
Treatment appears in FNA Volume 12. Treatment on page 537. Mentioned on page 532, 538, 540.

Plants candelabra-form, 20–40(–50) cm. Basal leaves persisting; petiole present or absent; blade linear-lanceolate to linear, margins deeply lobed to dentate. Cauline leaves: petiole absent; blade ovate-lanceolate to linear, to 15 cm, margins deeply to shallowly lobed or entire. Bracts green, ovate to lanceolate, 3.7–5.9 × 0.8–3.9 mm, width 1/8–2/3 length, not concealing capsule, margins entire. Flowers: sepals (2–)4–8(–10) mm; petals yellow to orange proximally, yellow distally, (6–)8–22 mm, apex acute to rounded; stamens 20+, 3–10 mm, filaments monomorphic, filiform, unlobed; styles 4–10 mm. Capsules clavate, 15–38 × 2–4 mm, axillary curved to 180° or S-shaped at maturity, usually inconspicuously longitudinally ribbed. Seeds 15–30, in 2+ rows distal to mid fruit, tan, dark-mottled, usually irregularly polygonal, occasionally triangular prisms proximal to mid fruit, surface tuberculate under 10× magnification; recurved flap over hilum absent; seed coat cell outer periclinal wall domed, domes on seed edges more than 1/2 as tall as wide at maturity. 2n = 36, 54.


Phenology: Flowering Mar–May.
Habitat: Sandy to rocky washes, fans, or flats, creosote-bush scrub, Joshua-tree or saguaro woodlands.
Elevation: 200–1500 m.

Distribution

V12 18-distribution-map.jpg

Ariz., Calif., Nev., Utah.

Discussion

Mentzelia jonesii is widespread throughout southeastern California and western and southern Arizona. However, tetraploid populations have been found only in California and far northwestern Arizona. Hexaploids in California have previously been called M. californica. The ranges of M. jonesii and the diploid, M. nitens, overlap in southern Inyo County, California, and these species are difficult to distinguish morphologically without mature seeds; sepal and petal lengths, which have sometimes been used to distinguish them, overlap completely.

Selected References

None.

Lower Taxa

None.
... more about "Mentzelia jonesii"
Joshua M. Brokaw +
(Urban & Gilg) H. J. Thompson & J. E. Roberts +
Mentzelia albicaulis var. jonesii +
Jones’s blazingstar +
Ariz. +, Calif. +, Nev. +  and Utah. +
200–1500 m. +
Sandy to rocky washes, fans, or flats, creosote-bush scrub, Joshua-tree or saguaro woodlands. +
Flowering Mar–May. +
M. californica +  and M. nitens var. jonesii +
Mentzelia jonesii +
Mentzelia sect. Trachyphytum +
species +