Mentzelia albicaulis
Mentzelia mexicana
small flower blazing star, small-flower evening star, white stem blazing star, white-stem evening star, white-stem stick-leaf
Mexican blazingstar, Mexico blazingstar
solitary, erect, straight;
branches distal or along entire stem, distal or proximal longest, antrorse, upcurved; hairy.
blade 24–82 × 11.7–29.1 mm, widest intersinus distance 3.4–19 mm;
proximal oblanceolate or elliptic, margins dentate, serrate, or pinnate, teeth or lobes 6–16, slightly antrorse or perpendicular to leaf axis, 1.4–5.1 mm;
distal elliptic to lanceolate, base usually not clasping, sometimes a few clasping, margins dentate, serrate, or pinnate, teeth or lobes 6–12, slightly antrorse or perpendicular to leaf axis, 2.5–6.7 mm;
abaxial surface with simple grappling-hook, complex grappling-hook, and usually needlelike trichomes, adaxial surface with simple grappling-hook and needlelike trichomes.
persisting;
petiole present or absent;
blade linear-lanceolate to linear, margins deeply to shallowly lobed.
petiole absent;
blade ovate-lanceolate to linear, to 15 cm, margins deeply to shallowly lobed or entire.
green, ovate to linear, 3.7–8.6 × 0.8–3.9 mm, width 1/6–2/3 length, not concealing capsule, margins 3-lobed or entire, lateral lobes never prominent.
margins entire.
sepals 1–5 mm;
petals orange proximally, yellow distally, 3–7(–8) mm, apex usually acute, rarely retuse;
stamens 20+, 3–5 mm, filaments monomorphic, filiform, unlobed;
styles 2–5 mm.
petals golden yellow, 10.2–15.3(–17) × 2.5–6.2 mm, apex rounded, glabrous abaxially;
stamens golden yellow, 5 outermost petaloid, filaments narrowly spatulate, slightly clawed, 9.9–14.4(–16.7) × 2–4.8 mm, without anthers, second whorl with anthers;
anthers straight after dehiscence, epidermis smooth;
styles 4.5–10.9 mm.
clavate, 8–28(–35) × 1.5–3.5 mm, longest capsules usually 15+ mm, axillary curved to 180° at maturity, usually inconspicuously longitudinally ribbed.
cup-shaped, 7.1–12.8 × 5.6–8.4 mm, length to 2 times diam., base rounded, not longitudinally ridged.
10–30, in 2+ rows distal to mid fruit, dark brown or tan, moderately to densely dark-mottled, usually irregularly polygonal, occasionally triangular prisms proximal to mid fruit, surface tuberculate under 10x 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.
coat anticlinal cell walls straight, papillae 8–12 per cell.
= 54, 72.
= 18.
Mentzelia albicaulis
Mentzelia mexicana
Mentzelia albicaulis is the most widespread species in sect. Trachyphytum and exhibits extensive morphological variation. Most populations of M. albicaulis are octoploid; however, hexaploids from southern California that have been called M. mojavensis and occasionally M. californica are also treated here as M. albicaulis. Two tetraploids in sect. Trachyphytum, M. montana and M. obscura, also have been treated previously as M. albicaulis (N. H. Holmgren et al. 2005). Both exhibit morphological forms and distributions overlapping with M. albicaulis. However, in most cases these species can be distinguished without chromosome counts, and their distinctiveness has been supported by phylogenetic analyses (J. M. Brokaw and L. Hufford 2010b).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
In the flora area, Mentzelia mexicana occurs in Brewster, Hudspeth, and Presidio counties.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
BC
CA
OR
WA
Flora NW
PNW Herbaria
SW CO Wildflowers
WildflowerSearch
iNaturalist
USDA Plants Database
