Mentzelia albescens
Mentzelia sect. Bartonia
wavy-leaf blazingstar
western star
solitary, erect, straight;
branches distal, distal longest, antrorse, straight; hairy.
blade 31–92(–157) × 10.5–27.6(–41) mm, widest intersinus distance 5.2–23.3(–29) mm;
proximal lanceolate or elliptic, margins serrate to pinnate, teeth or lobes 8–22, slightly antrorse, 1.8–6 mm;
distal lanceolate, base clasping, margins usually serrate to pinnate, occasionally entire, teeth or lobes (0–)10–20, slightly antrorse, 1.4–7.6 mm;
abaxial surface with simple grappling-hook, complex grappling-hook, and needlelike trichomes, adaxial surface with simple grappling-hook and needlelike trichomes.
basal rosette present, not persistent, proximalmost internodes to 10+ mm;
blade without broad basal lobes, margins entire, toothed, pinnate, or pinnatisect, flat.
margins entire.
petals golden yellow, 5.7–9.2 × 1.3–3 mm, apex usually acute, occasionally rounded, glabrous abaxially;
stamens golden yellow, 5 outermost petaloid, filaments narrowly spatulate, slightly clawed, 4.7–8.4 × 1–2.4 mm, without anthers, second whorl with anthers;
anthers straight after dehiscence, epidermis smooth;
styles 3.5–5.4 mm.
stamens all fertile or 5+ outer sterile;
filaments heteromorphic, outer dorsiventrally flattened, linear, elliptic, spatulate, or oblanceolate, usually petaloid, sometimes not, inner filiform, unlobed;
ovules (and seeds) oriented perpendicular to long axis of ovary.
cylindric, 13.6–23.5 × 5.1–7.8 mm, base tapering, not or slightly longitudinally ridged.
cup-shaped to lingulate or cylindric, straight.
coat anticlinal cell walls straight, papillae 4–17 per cell.
ovoid, flattened dorsiventrally, winged;
seed coat cells polygonal, ± isodiametric, anticlinal walls straight, wavy, or sinuous.
= 22.
Mentzelia albescens
Mentzelia sect. Bartonia
Phylogenetic analyses (J. J. Schenk and L. Hufford 2011) recovered representative populations of Mentzelia albescens from Texas and South America in a monophyletic group. Phylogenetic placement of these populations among lineages in sect. Bartonia, as well as a lack of morphological differentiation among North American and South American populations, suggests a recent dispersal to South America. In the flora area, this species is native to central and western Texas, and introduced in Kansas, Missouri, and Oklahoma.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Species 51 (51 in the flora).
In the following keys and descriptions, three trichome types are defined as follows. Simple grappling-hook trichomes have a cylindric stalk that is unbarbed except at the apex, which terminates with four (or sometimes fewer) retrorse barbs. Complex grappling-hook trichomes have a tapered stalk that is retrorsely barbed along its length and capped usually by four retrorse barbs. Needlelike trichomes have swollen bases resting on a pedestal formed by a ring of epidermal cells, are relatively long and pointed, and bear antrorse barbs or knobs along their length.
Leaf blade intersinus distance is measured across the leaf blade between opposite sinuses; for leaves with entire margins, it is the width of the leaf blade. Anther papillae and seed coat anticlinal wall shape can be observed at 10/x magnification; greater magnification (30–40/x) is needed to see seed coat cell papillae in species with numerous small papillae.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Petals white. | → 2 |
2. Anther epidermis papillate. | → 3 |
3. Leaf blade widest intersinus distances 9.5–29 mm. | M. hualapaiensis |
3. Leaf blade widest intersinus distances 0.8–9.1 mm. | → 4 |
4. 5 outermost stamens without anthers; New Mexico, Texas. | M. humilis |
4. 5 outermost stamens with anthers; Arizona. | M. canyonensis |
2. Anther epidermis smooth. | → 5 |
5. Petals 13–22.7 mm wide; stamens white to yellow. | M. decapetala |
5. Petals 1.9–10.3 mm wide; stamens white. | → 6 |
6. Petals 22.6–49 × 3.6–10.3 mm; bracts pinnate. | M. nuda |
6. Petals 14.7–22(–24.4) × 1.9–4.4 mm; bracts entire or dentate. | M. strictissima |
1. Petals light to golden yellow. | → 7 |
7. Petals hairy abaxially. | → 8 |
8. Branches perpendicular to stem, especially proximal and mid-stem, or slightly antrorse, especially distal, ± equal; Montrose County, Colorado. | M. paradoxensis |
8. Branches antrorse, proximal longer than distal, all usually extending to near the distal end of plant; Arizona, Colorado (including Montrose County), New Mexico, Utah. | → 9 |
9. 5 outermost stamens with anthers; margins of proximal leaf blades with teeth 0.5–4 mm; Colorado. | M. marginata |
9. 5 outermost stamens usually without anthers; margins of proximal leaf blades with teeth or lobes 1.2–6(–9) mm, always some more than 4 mm; Arizona, Colorado, New Mexico, Utah. | M. cronquistii |
7. Petals glabrous abaxially. | → 10 |
10. Anther epidermis papillate. | → 11 |
11. 5 outermost stamens with anthers. | → 12 |
12. Leaf blades 4–12.2 mm wide, always some more than 10 mm wide, margins usually entire, rarely dentate, teeth 0(–4), 0.1–1.4 mm; seed coat cell papillae 3–5 per cell; Utah. | M. argillosa |
12. Leaf blades 1.5–8.8 mm wide, margins entire, dentate, or pinnate, teeth or lobes 0–8 (always some leaves with 5+ teeth or lobes), 0.1–2 mm (always some more than 1.4 mm); seed coat cell papillae 5–8 per cell; Nevada. | M. argillicola |
11. 5 outermost stamens without anthers. | → 13 |
13. Leaf blade widest intersinus distances 9.5–29 mm. | M. hualapaiensis |
13. Leaf blade widest intersinus distances 1–4.2 mm. | → 14 |
14. Second whorl of stamens without anthers. | M. perennis |
14. Second whorl of stamens with anthers. | → 15 |
15. Seed coat anticlinal cell walls straight, papillae 38–45 per cell; Texas. | M. saxicola |
15. Seed coat anticlinal cell walls sinuous, papillae 6–12 per cell; New Mexico. | M. todiltoensis |
10. Anther epidermis smooth. | → 16 |
16. Capsules longitudinally ridged. | M. rusbyi |
16. Capsules not longitudinally ridged. | → 17 |
17. Stems multiple, from subterranean branching caudices. | → 18 |
18. 5 outermost stamens without anthers. | M. springeri |
18. 5 outermost stamens with anthers. | → 19 |
19. Bases of distal leaf blades clasping. | → 20 |
20. Leaf blade surfaces densely hairy, whitish, abaxial surfaces with complex grappling-hook and needlelike trichomes; Ash Meadows, Nye County, Nevada. | M. leucophylla |
20. Leaf blade surfaces moderately hairy, green, abaxial surfaces with complex grappling-hook trichomes only; se California and s Nevada (including Nye County). | → 21 |
21. Leaf blades 5.8–9.1 mm wide, widest intersinus distances 4.6–7.1 mm; margins of distal leaf blades with 0–6 teeth; seed coat cell papillae 15–46 per cell. | M. tiehmii |
21. Leaf blades 7.6–41.2 mm wide, widest intersinus distances 5.1–35.3 mm; margins of distal leaves with 6–16 teeth; seed coat cell papillae 6–17 per cell. | M. oreophila |
19. Bases of distal leaf blades not clasping. | → 22 |
22. Margins of proximal leaf blades 3-fid or pinnate to pinnatisect (rarely entire in M. librina). | → 23 |
23. Filaments of 5 outermost stamens broadly spatulate, strongly clawed. | → 24 |
24. Margins of proximal leaf blades pinnate to pinnatisect, lobes 4–12. | M. uintahensis |
24. Margins of proximal leaf blades usually 3-fid, rarely entire or pinnate, teeth or lobes usually 2, rarely 0 or 4. | M. librina |
23. Filaments of 5 outermost stamens narrowly spatulate or oblanceolate, slightly clawed. | → 25 |
25. Petals 2.9–3.8 mm wide; filaments of 5 outermost stamens less than 1.3–1.9 mm wide; Utah. | M. flumensevera |
25. Petals 5.1–9 mm wide; filaments of 5 outermost stamens 2–4.5 mm wide; Colorado. | M. multicaulis |
22. Margins of proximal leaf blades entire or dentate to serrate. | → 26 |
26. Stems glabrescent, smooth to the touch. | M. polita |
26. Stems hairy. | → 27 |
27. Margins of proximal leaves entire. | → 28 |
28. Petals 7.4–11 × 2.6–3.4 mm; margins of distal leaf blades entire; filaments of 5 outermost stamens slightly clawed; Arizona. | M. memorabilis |
28. Petals 12.5–17.2 × 6.1–11.2 mm; margins of distal leaf blades entire or dentate; filaments of 5 outermost stamens strongly clawed; Colorado. | M. rhizomata |
27. Margins of proximal leaf blades dentate or serrate, with 4–12 teeth. | → 29 |
29. Petals 6.7–9.2 mm wide; seed coat cell papillae 11–15 per cell. | M. goodrichii |
29. Petals 2.3–5.9 mm wide; seed coat cell papillae 3–6 per cell. | → 30 |
30. Stems zigzag; margins of proximal leaf blades with 4–6 teeth, each 0.5–0.6 × 1.2–1.5 mm. | M. shultziorum |
30. Stems straight; margins of proximal leaf blades with 8–12 teeth, each 1–4 × 1.7–6 mm. | M. puberula |
17. Stems solitary or, if multiple, from ground-level caudices. | → 31 |
31. 5 outermost stamens not petaloid, with anthers, filaments linear to narrowly elliptic or narrowly spatulate, 0.5–2(–2.5) mm wide, if narrowly spatulate, to 1.5 mm wide. | → 32 |
32. Petals 23.5–70 mm; styles 20.4–57 mm; 5 outermost stamens 17.7–55 mm. | M. laevicaulis |
32. Petals (6.1–)7.3–15.8(–18) mm; styles 3.7–13 mm; 5 outermost stamens 4–13.2 mm. | → 33 |
33. Petals 11.7–15.8(–18) mm; 5 outermost stamens 10.2–13.2 mm. | M. inyoensis |
33. Petals (6.1–)7.3–10 mm; 5 outermost stamens 4–8 mm. | M. candelariae |
31. 5 outermost stamens petaloid, with or without anthers, filaments narrowly spatulate to elliptic or oblanceolate, 1–9.7 mm wide, if narrowly spatulate and less than 1.5 mm wide, then without anthers. | → 34 |
34. Margins of distal leaf blades pinnatisect (sometimes pinnate in M. laciniata). | → 35 |
35. Petals 30–42.2 mm; 5 outermost stamens 27–37.4 mm; styles 24–32.4 mm. | M. conspicua |
35. Petals 8.3–23.8(–26) mm; 5 outermost stamens 6.5–20.4 mm; styles 6.1–12.5(–14) mm. | → 36 |
36. Petals 8.3–13 mm; 5 outermost stamens 6.5–10.7 mm; Colorado, Nevada, Utah. | M. lagarosa |
36. Petals 13–23.8(–26) mm; 5 outermost stamens 10.2–20.4 mm; Arizona, Colorado, New Mexico. | → 37 |
37. Lobes of distal leaf blades strongly antrorse; branches upcurved; Arizona, New Mexico. | M. holmgreniorum |
37. Lobes of distal leaf blades slightly antrorse or perpendicular to leaf axis; branches straight; Arizona, Colorado, New Mexico. | → 38 |
38. Seed coat cell papillae 42–48 per cell; Chuska Mountains of Arizona and New Mexico. | M. filifolia |
38. Seed coat cell papillae 5–14 per cell; Colorado, New Mexico (not Chuska Mountains). | M. laciniata |
34. Margins of distal leaf blades entire, dentate, serrate, or pinnate. | → 39 |
39. Bases of distal leaf blades clasping (rarely a few not clasping in M. pterosperma). | → 40 |
40. Capsules cup-shaped; Arizona, California, Colorado, Nevada, Utah. | M. pterosperma |
40. Capsules cylindric; Kansas, Missouri, Oklahoma, Texas. | M. albescens |
39. Bases of distal leaf blades not clasping (sometimes a few clasping in M. mexicana). | → 41 |
41. Filaments of 5 outermost stamens strongly clawed; on black (to sometimes reddish) volcanic cinder cone soils in San Francisco Volcanic Field, Coconino County, Arizona. | M. collomiae |
41. Filaments of 5 outermost stamens slightly clawed; not on black (to sometimes reddish) volcanic cinder cone soils in San Francisco Volcanic Field, Coconino County, Arizona. | → 42 |
42. Seed coat cell anticlinal walls straight. | → 43 |
43. Capsule length more than 2 times diam. (occasionally a few slightly less in M. reverchonii). | → 44 |
44. Styles 8.7–11.4(–13) mm; Colorado, New Mexico, Oklahoma, Texas. | M. reverchonii |
44. Styles 5.6–7.8 mm; Montana, Utah, Wyoming. | M. pumila |
43. Capsule length to 2 times diam. (sometimes a few more in M. longiloba). | → 45 |
45. Capsule bases tapering; seed coat cell papillae 4–6 per cell. | M. longiloba |
45. Capsule bases rounded; seed coat cell papillae 8–45 per cell. | → 46 |
46. Seed coat cell papillae 8–12 per cell; leaf blade widest intersinus distances 3.4–19 mm. | M. mexicana |
46. Seed coat cell papillae 38–45 per cell; leaf blade widest intersinus distances 1.6–3.4 mm. | M. saxicola |
42. Seed coat cell anticlinal walls wavy to sinuous. | → 47 |
47. Margins of proximal leaves with 4–12 teeth or lobes. | → 48 |
48. Plants candelabra-form; proximal branches not decumbent; largest leaf trichomes with pearly white bases; leaf blade margin teeth with proximal side antrorse, distal side perpendicular to leaf axis; Arizona, Nevada, Utah. | M. integra |
48. Plants bushlike; proximal branches decumbent; largest leaf trichomes without pearly white bases; leaf blade margin teeth or lobes perpendicular to leaf axis; c Colorado. | M. densa |
47. Margins of proximal leaves with 14–38 teeth or lobes (occasionally 10–38 in M. speciosa). | → 49 |
49. Seed coat cell anticlinal walls wavy; petals golden yellow; leaf blades 43.6–233 mm, always some 146+ mm. | M. speciosa |
49. Seed coat cell anticlinal walls sinuous; petals light to golden yellow; leaf blades 32.8–125(–146) mm. | → 50 |
50. 5 outermost stamens with anthers. | → 51 |
51. Leaf blade widest intersinus distances 2.3–7.1 mm, always some leaves 4+ mm; branches upcurved. | M. longiloba |
51. Leaf blade widest intersinus distances 1–2.9 mm; branches straight. | M. sivinskii |
50. 5 outermost stamens without anthers. | → 52 |
52. Leaf blade widest intersinus distances 1–3.9 mm; petals light yellow. | M. procera |
52. Leaf blade widest intersinus distances 2.1–13.7(–14) mm, always some leaves 4+ mm; petals light to golden yellow. | → 53 |
53. Seed coat cell papillae 10–21 or 67–106 per cell; Arizona, California, Colorado, New Mexico, Utah. | M. longiloba |
53. Seed coat cell papillae 29–48 per cell; Colorado, Nebraska, New Mexico, Wyoming. | → 54 |
54. Branches distal or along entire stem, straight. | M. chrysantha |
54. Branches distal, upcurved. | M. multiflora |
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