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University of California, Berkeley | |||||
Jepson Herbarium | |||||
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Jepson eFlora
Key to families | Table of families and genera
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(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 cylindric or barrel-shaped, or fruit 3–6 mm wide and urn-shaped; seeds transverse-folded or ridged at middle with beak-like end, fusiform and ribbed lengthwise, or lenticular and winged; annual, biennial, or perennial herb
2. Filament distal lobes 2, anther generally on thin stalk between lobes
3. Flower bract 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 sessile; fruit erect, 13–25 mm; w Sonoran Desert ..... M. hirsutissima
5' Upper leaves petioled; fruit erect to reflexed, 9–18 mm; c Mojave Desert ..... 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 linear filaments, <= 2 mm wide, with anthers; petal tips acute; fruit 11–44 mm
9. Petals < 3 cm ..... M. inyoensis
9' Petals > 3 cm ..... M. laevicaulis
8' 5 outermost stamens with spoon-shaped to oblanceolate filaments, >= 1 mm wide, with anthers or not; petal tips acute to round or obtuse; 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 entire, linear to narrowly elliptic or oblanceolate ..... M. polita
12' Lower leaves lobed to toothed, obovate to ovate, elliptic, or oblanceolate
13. Upper leaves deltate to cordate, 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 recurved flap over attachment scar; 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 Sierra Nevada Foothills, s High Sierra Nevada ..... M. crocea
25' Petals generally 16–33 mm wide; San Joaquin Valley, e San Francisco Bay Area, n Inner South Coast Ranges ..... 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 Mojave Desert ..... M. eremophila (2)
28' Petals orange to yellow, base red to orange; s Sierra Nevada Foothills, s San Joaquin Valley, s Outer South Coast Ranges, n Western Transverse Ranges ..... 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 San Francisco Bay Area, South Coast Ranges, Western Transverse Ranges, w San Gabriel Mountains ..... M. gracilenta
31' Desert scrub, Joshua-tree woodland; San Gabriel Mountains, e Peninsular Ranges, sw Mojave Desert, w Sonoran Desert ..... 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 spreading; desert scrub, Joshua-tree woodland ..... M. ravenii (2)
36' Stem generally erect; pine/oak woodland, grassland ..... M. veatchiana (3)
Citation for the whole project: Jepson Flora Project (eds.) [year] Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html [accessed on month, day, year]
Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on [month, day, year].
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