Mentzelia isolata

Gentry

Brittonia 6: 322. 1948.

Common names: Isolated blazingstar
Treatment appears in FNA Volume 12. Treatment on page 528. Mentioned on page 527, 529.

Plants annual, without caudices or tubers. Stems erect, to 70 cm. Leaves: petiole to 25 mm (proximal leaves), absent (distal leaves); blade usually lanceolate to hastate, rarely elliptic, basally lobed, sometime with 2 pairs of lobes, or unlobed, to 14 × 4.5 cm, base obliquely obtuse to acute, margins shallowly serrate, apex acute. Pedicels (fruiting) 0.5–0.8 × 1–2 mm (often appearing absent because thick and continuous with capsule). Flowers: petals orange, 5–7 × 2.3–4 mm, apex cuspidate, hairy on apex and abaxially near apex; stamens 8–12, 4–5.3 mm, filaments heteromorphic, 5 outermost narrowly spatulate, inner filiform; styles 3.8–5.5 mm. Capsules clavate or funnelform, 12–27 × 3–5 mm, base tapering gradually, capsule and pedicel not well-differentiated. Seeds 8–12 per capsule, pyriform, without transverse folds. 2n = 20.


Phenology: Flowering Aug–Oct.
Habitat: Arroyo and canyon bottoms, rocky slopes.
Elevation: 1000–1900 m.

Distribution

V12 644-distribution-map.jpg

Ariz., Mexico (Sinaloa), Mexico (Sonora)

Discussion

Mentzelia isolata intergrades with both M. aspera and M. asperula in southern Arizona. Typically, M. isolata can be distinguished from both M. aspera and M. asperula because its leaf blades are more than two times as long as wide, whereas those of the latter two species are less than two times as long as wide.

Selected References

None.

Lower Taxa

None.
... more about "Mentzelia isolata"
heteromorphic +
inner +  and outer +
unlobed +, filiform +, spatulate +  and flattened +
Larry Hufford +
Gentry +
tapering +, obliquely obtuse +  and acute +
0 cm0 mm <br />0 m <br /> (14 cm140 mm <br />0.14 m <br />) +
unlobed;lobed;usually lanceolate;hastate +
0 cm0 mm <br />0 m <br /> (4.5 cm45 mm <br />0.045 m <br />) +
curved +  and straight +
1.2 cm12 mm <br />0.012 m <br /> (2.7 cm27 mm <br />0.027 m <br />) +
funnel +  and clavate +
not well-differentiated +
0.3 cm3 mm <br />0.003 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
Isolated blazingstar +
Ariz. +, Mexico (Sinaloa) +  and Mexico (Sonora) +
1000–1900 m. +
curved +  and straight +
s--shaped +, clavate +, urceolate +, ovoid +, cylindric +, subcylindric +, lingulate +  and cup-shaped +
Arroyo and canyon bottoms, rocky slopes. +
free +  and adnate +
cauline +  and basal +
crenate +, toothed +  and entire +
apical +, subapical +  and inferior +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (?) +  and 0.08 cm0.8 mm <br />8.0e-4 m <br /> (?) +
not well-differentiated +
1mm +  and 2mm +
inconspicuous +
connate +  and distinct +
spreading +  and erect +
hairy +  and glabrous +
obovate +, oblanceolate +, elliptic +, ovate +  and spatulate +
0.23 cm2.3 mm <br />0.0023 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
0 cm0 mm <br />0 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
Flowering Aug–Oct. +
pyriform +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.45 cm4.5 mm <br />0.0045 m <br />) +
persistent +
lanceolate +  and narrowly ovate +
adnate +, free +  and distinct +
included +  and exserted +
8 +  and 12 +
0.4 cm4 mm <br />0.004 m <br /> (0.53 cm5.3 mm <br />0.0053 m <br />) +
0 cm0 mm <br />0 m <br /> (70 cm700 mm <br />0.7 m <br />) +
papillate +
3-lobed +  and lingulate +
0.38 cm3.8 mm <br />0.0038 m <br /> (0.55 cm5.5 mm <br />0.0055 m <br />) +
Mentzelia isolata +
Mentzelia sect. Mentzelia +
species +
dendritic +  and unbranched +
sinuous +