Jepson eFlora: Key page
Vascular Plants of California
Key to families | Table of families and genera

Key to Mentzelia

View taxon page for Mentzelia

(For a list of species in Mentzelia, use the above link.)

Jepson Manual glossary definitions can be seen by moving your cursor over words underlined with dots.

1. Fruit > 4 mm wide, cup-shaped to  or barrel-shaped, or fruit 3–6 mm wide and seeds transverse-folded or ridged at middle with beak-like end,  and ribbed lengthwise, or lenticular and winged; annualbiennial, or  herb

2. Filament distal  2, anther generally on thin stalk between lobes

3. Flower  white-scarious, margin ± green ..... M. involucrata

3' Flower bract ± all green

4. Anther stalk between filament lobes generally < lobes; seeds narrowed at middle ..... M. tricuspis

4' Anther stalk generally >= filament lobes; seeds widest at middle

5. Distal leaves ; fruit , 13–25 mm; w DSon ..... M. hirsutissima

5' Distal leaves petioled; fruit erect to , 9–18 mm; c DMoj ..... M. tridentata

2' Filament distal lobes 0

6. Petals 8; annual ..... M. reflexa

6' Petals 5 or petals and petal-like staminodes 10; generally biennial or perennial herb, sometimes annual in M. pterosperma

7. Fruit urn-shaped and gradually narrowing; seeds not winged, all filaments thread-like ..... M. torreyi

7' Fruit cup-shaped to cylindric; seeds winged; 5 outer stamens with filaments wider than thread-like

8. 5 outermost stamens with  filaments, <= 2 mm wide, with antherspetal tips ; fruit 11–44 mm

9. Petals 11–18 mm..... M. inyoensis

8' 5 outermost stamens with spoon-shaped to oblanceolate filaments, >= 1 mm wide, with anthers or not; petal tips acute to rounded or ; fruit 4.5–18 mm

10. 5 outermost stamens generally without anthers; petal tips acute to long-tapered ..... M. pterosperma

10' 5 outermost stamens with or without anthers; petal tips rounded to obtuse

11. Fruit generally cylindric, >= 1 cm; anthers not spiral-twisted in age ..... M. longiloba var. longiloba

11' Fruit cup-shaped, generally <= 1 cm; anthers spiral-twisted in age

12. Proximal leaves generally , linear to narrowly  or oblanceolate ..... M. polita

12' Proximal leaves lobed to toothed, obovate to , elliptic, or oblanceolate

13. Distal leaves  to , base clasping stem ..... M. oreophila

13' Distal leaves ovate to broadly elliptic, base tapering, not clasping stem ..... M. puberula

1' Fruit < 4(5) mm wide, cylindric to obconic, if 4–5 mm wide, then obconic only; seeds irregular-rounded to irregular-angular or prism-shaped; annual

14. Seed row 1 distal to mid-fruit; seeds ± prism-shaped, ×-section generally triangular with grooves along longitudinal edges

15. Outer 5 filaments widened and distally 2-lobed ..... M. micrantha

15' Outer filaments ± thread-like, not lobed

16. Proximal leaves generally lobed (toothed); style 3–6.5 mm; < 1200 m ..... M. affinis

16' Proximal leaves generally entire or toothed; style generally 1–3.5 mm; > 900 m ..... M. dispersa

14' Seed rows ± 3 distal to mid-fruit; seeds irregular-rounded to -angular (winged) distal to mid-fruit, proximal to mid-fruit ×-section occasionally triangular with grooves along longitudinal edges

17. Flower bracts generally entire, generally green only, sometimes with inconspicuous white base in M. monoensis

18. Petals generally < 8 mm

19. Seeds tan and moderately to densely mottled brown to black in age; seed coat cells pointed or domed, in age > 1/2 tall as wide on seed surface edges ..... M. albicaulis (4)

19' Seeds tan, not or sparsely mottled in age; seed coat cells flat-surfaced to domed, in age < 1/2 tall as wide on seed surface edges

20. Seed coat cells generally flat-surfaced in age; D ..... M. desertorum

20' Seed coat cells generally domed in age

21. Stems densely bristly-hairy; fruit curved < 20°; SNE (Mono Basin, Mono Co.) ..... M. monoensis

21' Stems glabrous to ± hairy; curved < 250°; D..... M. obscura

18' Petals generally >= 8 mm

22. Sepals generally > 8 mm; style 7–15 mm ..... M. eremophila (2)

22' Sepals generally <= 8 mm; style 4–10 mm

23. Seeds without conspicuous  flap over attachment ; seed coat cells pointed or domed, in age > 1/2 tall as wide on seed surface edges ..... M. jonesii

23' Seeds with conspicuous recurved flap over attachment scar; seed coat cells domed, in age < 1/2 tall as wide on seed surface edges ..... M. nitens

17' Flower bracts toothed to lobed or flower bracts entire with ± white base and green margin

24. Flower bracts green only

25. Styles > 15 mm

26. Petals generally 8–17 mm wide; c&s SNF, s SNH ..... M. crocea

26' Petals generally 16–33 mm wide; SnJV, e SnFrB, n SCoRI ..... M. lindleyi

25' Styles < 15 mm

27. Petals generally < 8 mm

28. Petals orange to orange-yellow, base generally red to orange; flower bracts 3–7-toothed to lobed (entire); fruit generally curved < 40° ..... M. veatchiana (3)

28' Petals yellow, base generally orange; flower bracts 3-toothed to entire; fruit generally curved < 180° ..... M. albicaulis (4)

27' Petals generally >= 8 mm

29. Petals yellow only; w DMoj ..... M. eremophila (2)

29' Petals orange to yellow, base red to orange; s SNF, Teh, SnJV, SCoR, n WTR

30. Petals bright yellow, yellow to orange at base (in a few individuals in population rarely coppery orange, deep orange to red at base) ..... M. pectinata var. chrysopetala

30' Petals coppery orange, deep orange to red at base ..... M. pectinata var. pectinata

24' Flower bracts ± white at base, margin green

31. Flower bracts ± concealing fruits, mostly white-scarious; inflorescence dense ..... M. congesta

31' Flower bracts not concealing fruits, ± white proximal to middle; inflorescence open to ± dense

32. Petals generally > 8 mm, yellow, base generally orange; seed coat cells domed, in age ± 1/2 tall as wide on seed surface edges

33. Pine/oak woodland; s SnFrB, SCoR, WTR, w SnGb ..... M. gracilenta

33' Desert scrub, Joshua-tree woodland; SnGb, e PR, sw DMoj, w DSon ..... M. ravenii (2)

32' Petals generally < 8 mm, orange to yellow, base generally red to orange; seed coat cells generally pointed or domed, in age > 1/2 tall as wide on seed surface edges

34. Styles generally < 3.5 mm; longest mature fruit generally > 10 mm

35. Flower bracts entire to 3-toothed; ± white base of bracts faint, small

36. Flower bracts 3-toothed to entire; longest mature fruit generally > 15 mm, generally curved < 180° widely distributed..... M. albicaulis (4)

36' Flower bracts entire; mature fruit 6–15 mm, erect to curved < 20° SNE (Mono Basin, Mono Co.) ..... M. monoensis

35' Flower bracts 3–7-toothed; ± white base of bracts prominent, generally conspicuously extending outwards from midvein; longest mature fruit generally < 17 mm, curved < 45°; 600–3400 m ..... M. montana

34' Styles generally >= 3.5 mm; longest mature fruit generally > 15 mm

37. Petals orange to orange-yellow, base generally red to orange; flower bracts 3–7-toothed to lobed (entire) ..... M. veatchiana (3)

37' Petals yellow, base generally orange; flower bracts 7-toothed to entire

38. Flower bracts 3-toothed to entire, width < 2/3 length; ± white base of bracts faint, small; fruit generally curved < 180° ..... M. albicaulis (4)

38' Flower bracts 3–7-toothed, width > 1/3 length; ± white base of bracts prominent, generally conspicuously extending outwards from midvein; fruit generally curved < 40°

39. Stem generally desert scrub, Joshua-tree woodland ..... M. ravenii (2)

39' Stem generally erect; pine/oak woodland, grassland ..... M. veatchiana (3)

 

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Citation for the whole project: Jepson Flora Project (eds.) . Jepson eFlora, https://ucjeps.berkeley.edu/eflora/ [accessed on ]

Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on .

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