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Vascular Plants of California
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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. Upper leaves ; fruit , 13–25 mm; w DSon ..... M. hirsutissima

5' Upper 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; biennial or perennial herb

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

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

10. 5 outermost stamens without anther; 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

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

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

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

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

13' Upper leaves ovate to broadly elliptic, base 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 rows 1 above 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. Lower leaves generally lobed (toothed); style 3–6.5 mm; < 1200 m ..... M. affinis

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

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

17. Flower bracts generally entire, green only

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 ..... M. desertorum

20' Seed coat cells domed in age ..... M. obscura

18' Petals generally >= 8 mm

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

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

22. 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

22' 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

23. Flower bracts green only

24. Styles > 15 mm

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

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

24' Styles < 15 mm

26. Petals generally < 8 mm

27. 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)

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

26' Petals generally >= 8 mm

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

28' Petals orange to yellow, base red to orange; s SNF, s SnJV, s SCoRO, n WTR ..... M. pectinata

23' Flower bracts ± white at base, margin green

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

29' Flower bracts not concealing fruits, ± white below middle; inflorescence open to ± dense

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

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

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

30' 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

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

33. Flower bracts 3-toothed to entire; ± white base of bracts faint, small; longest mature fruit generally > 15 mm, generally curved < 180°; below 2300 m ..... M. albicaulis (4)

33' 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

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

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

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

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

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

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

36' 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, http://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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