Mentzelia ravenii

H. J. Thompson & J. E. Roberts

Phytologia 21: 285. 1971.

Common names: Raven’s blazingstar
Endemic
Treatment appears in FNA Volume 12. Treatment on page 541. Mentioned on page 533, 537, 542.

Plants candelabra-form, (5–) 20–45 cm. Basal leaves persisting; petiole present or absent; blade linear-lanceolate, margins deeply to shallowly lobed. Cauline leaves: petiole absent; blade ovatelanceolate to lanceolate, to 18 cm, margins deeply lobed to dentate. Bracts green with prominent white base usually conspicuously extending outwards from midvein, ovate, 5.6–8.4 × 1.8–3.9 mm, width 1/5–2/3 length, not concealing capsule, margins 3–5-lobed. Flowers: sepals 2–6 mm; petals orange proximally, yellow distally, 5–11 (–13) mm, apex retuse; stamens 20+, 3–7 mm, filaments monomorphic, filiform, unlobed; styles 3.5–8 mm. Capsules clavate, 8–23 × 2–3 mm, axillary curved to 45° 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 or equal to 1/2 as tall as wide at maturity. 2n = 36.


Phenology: Flowering Mar–May.
Habitat: Sandy desert foothills, roadsides, desert scrub, Joshua-tree woodlands.
Elevation: 300–1200 m.

Discussion

Mentzelia ravenii is narrowly distributed, with most populations limited to desert foothills on the northern edge of the San Gabriel Mountains in northeastern Los Angeles County. Populations of M. ravenii with relatively large flowers with yellow petals are often found growing under desert shrubs in mixed populations with M. veatchiana, which has relatively small flowers with orange petals in this area. A few tetraploid populations from western Riverside County have also been called M. ravenii (J. E. Zavortink 1966); further work is needed to confirm that these represent the same species. See 72. M. gracilenta for discussion of similarities it shares with M. ravenii.

Selected References

None.

Lower Taxa

None.

"not elongating" is not a number.

... more about "Mentzelia ravenii"
monomorphic +
unlobed +  and filiform +
Joshua M. Brokaw +
H. J. Thompson & J. E. Roberts +
not +  and persistent +
Mentzelia +
ovatelanceolate;lanceolate +
0 cm0 mm <br />0 m <br /> (18 cm180 mm <br />0.18 m <br />) +
1/(1/5-2/3) +
0.56 cm5.6 mm <br />0.0056 m <br /> (0.84 cm8.4 mm <br />0.0084 m <br />) +
0.18 cm1.8 mm <br />0.0018 m <br /> (0.39 cm3.9 mm <br />0.0039 m <br />) +
0.8 cm8 mm <br />0.008 m <br /> (2.3 cm23 mm <br />0.023 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
Raven’s blazingstar +
300–1200 m. +
curved +  and straight +
s--shaped +, clavate +, urceolate +, ovoid +, cylindric +, subcylindric +, lingulate +  and cup-shaped +
Sandy desert foothills, roadsides, desert scrub, Joshua-tree woodlands. +
free +  and adnate +
2-lobed +, unlobed +  and filiform +
cauline +  and basal +
pinnatisect +, pinnate +  and entire +
3-5-lobed +, deeply lobed +  and dentate +
elliptic +  and linear +
apical +, subapical +  and inferior +
inconspicuous +
1.1 cm11 mm <br />0.011 m <br /> (1.3 cm13 mm <br />0.013 m <br />) +
yellow +  and orange +
connate +  and distinct +
spreading +  and erect +
hairy +  and glabrous +
obovate +, oblanceolate +, elliptic +, ovate +  and spatulate +
0.5 cm5 mm <br />0.005 m <br /> (1.1 cm11 mm <br />0.011 m <br />) +
Flowering Mar–May. +
0 cm0 mm <br />0 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
dark-mottled +  and tan +
triangular +  and polygonal +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.45 cm4.5 mm <br />0.0045 m <br />) +
persistent +
lanceolate +  and narrowly ovate +
0.2 cm2 mm <br />0.002 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
adnate +, free +  and distinct +
included +  and exserted +
8 +  and 45 +
0.3 cm3 mm <br />0.003 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
decumbent +, clambering +  and erect +
papillate +
3-lobed +  and lingulate +
0.35 cm3.5 mm <br />0.0035 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
tuberculate +
Mentzelia ravenii +
Mentzelia sect. Trachyphytum +
species +
dendritic +  and unbranched +
straight +
5 cm50 mm <br />0.05 m <br /> (20 cm200 mm <br />0.2 m <br />) +