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dal-pega, rough stickleaf, tropical blazingstar, tropical stickleaf

Pacific blazing star

Habit Plants annual, without caudices or tubers. Plants candelabra-form, 8–45 cm.
Stems

erect to decumbent, to 30 cm.

Leaves

petiole 10–65 mm;

blade hastate to ovate, usually basally lobed, sometimes unlobed, to 18 × 10 cm, base cuneate to truncate, margins serrate to crenate, apex acute.

Basal leaves

persisting;

petiole present or absent;

blade linear-lanceolate to linear, margins usually irregularly deeply lobed, lobes pointed.

Cauline leaves

petiole absent;

blade ovate-lanceolate to linear, to 15(–22) cm, margins few-lobed or entire.

Bracts

green, ovate to ovate-lanceolate, 2.9–8.2 × 1.1–1.9 mm, width 1/8–1/2 length, not concealing capsule, margins entire.

Pedicels

(fruiting) 1–3 × 2 mm (often appearing absent because thick and continuous with capsule).

Flowers

petals orange or yellow, 5–15 × 3–7 mm, apex cuspidate, hairy abaxially at apex;

stamens 20–30, 5 mm, filaments heteromorphic, 5 outermost narrowly spatulate, inner filiform;

style 5 mm.

sepals 2–6 mm;

petals yellow to orange proximally, yellow distally, 3–8 mm, apex rounded or acute apex;

stamens 20–40, 2–7 mm, filaments monomorphic, filiform, unlobed;

styles 2–6 mm.

Capsules

subcylindric to clavate, 9–30 × 3–3.5 mm, base tapering gradually, capsule and pedicel not well-differentiated.

clavate, 11–31 × 1.5–3 mm, axillary curved to 250° at maturity, usually inconspicuously longitudinally ribbed.

Seeds

5–9 per capsule, pyriform to oblong, without transverse folds.

15–50, in 2+ rows distal to mid fruit, tan, usually not, occasionally sparsely, dark-mottled, usually irregularly polygonal, occasionally triangular prisms proximal to mid fruit, surface colliculate under 10x magnification; recurved flap over hilum absent;

seed coat cell outer periclinal wall domed, domes on seed edges less than 1/2 as tall as wide at maturity.

2n

= 20.

= 36.

Mentzelia aspera

Mentzelia obscura

Phenology Flowering Aug–Oct. Flowering Feb–May.
Habitat Arroyo and canyon bottoms, grasslands, desert scrub, riparian cottonwood and willow vegetation. Sandy to rocky washes or slopes, desert scrub, Joshua-tree woodlands, roadsides.
Elevation 100–2000 m. (300–6600 ft.) 200–1700 m. (700–5600 ft.)
Distribution
from FNA
AZ; Mexico; Central America; South America; West Indies [Introduced in Atlantic Islands (Cape Verde Islands)]
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; NV; UT; Mexico (Baja California, Sonora)
[WildflowerSearch map]
[BONAP county map]
Discussion

Mentzelia aspera is uncommon in southern Arizona. It is the most widespread species of the genus and is regarded as weedy by some authors (H. J. Thompson and A. M. Powell 1981).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Mentzelia obscura is morphologically intermediate to M. desertorum and M. albicaulis and is known to occur in mixed populations with both species. Reliable discrimination among these species usually requires mature seeds.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 12, p. 528. FNA vol. 12, p. 540.
Parent taxa Loasaceae > Mentzelia > sect. Mentzelia Loasaceae > Mentzelia > sect. Trachyphytum
Sibling taxa
M. affinis, M. albescens, M. albicaulis, M. argillicola, M. argillosa, M. asperula, M. candelariae, M. canyonensis, M. chrysantha, M. collomiae, M. congesta, M. conspicua, M. crocea, M. cronquistii, M. decapetala, M. densa, M. desertorum, M. dispersa, M. eremophila, M. filifolia, M. floridana, M. flumensevera, M. goodrichii, M. gracilenta, M. hirsutissima, M. holmgreniorum, M. hualapaiensis, M. humilis, M. integra, M. involucrata, M. inyoensis, M. isolata, M. jonesii, M. laciniata, M. laevicaulis, M. lagarosa, M. leucophylla, M. librina, M. lindheimeri, M. lindleyi, M. longiloba, M. marginata, M. memorabilis, M. mexicana, M. micrantha, M. mollis, M. monoensis, M. montana, M. multicaulis, M. multiflora, M. nitens, M. nuda, M. obscura, M. oligosperma, M. oreophila, M. pachyrhiza, M. packardiae, M. paradoxensis, M. pectinata, M. perennis, M. polita, M. procera, M. pterosperma, M. puberula, M. pumila, M. ravenii, M. reflexa, M. reverchonii, M. rhizomata, M. rusbyi, M. saxicola, M. shultziorum, M. sivinskii, M. speciosa, M. springeri, M. strictissima, M. thompsonii, M. tiehmii, M. todiltoensis, M. torreyi, M. tricuspis, M. tridentata, M. uintahensis, M. veatchiana
M. affinis, M. albescens, M. albicaulis, M. argillicola, M. argillosa, M. aspera, M. asperula, M. candelariae, M. canyonensis, M. chrysantha, M. collomiae, M. congesta, M. conspicua, M. crocea, M. cronquistii, M. decapetala, M. densa, M. desertorum, M. dispersa, M. eremophila, M. filifolia, M. floridana, M. flumensevera, M. goodrichii, M. gracilenta, M. hirsutissima, M. holmgreniorum, M. hualapaiensis, M. humilis, M. integra, M. involucrata, M. inyoensis, M. isolata, M. jonesii, M. laciniata, M. laevicaulis, M. lagarosa, M. leucophylla, M. librina, M. lindheimeri, M. lindleyi, M. longiloba, M. marginata, M. memorabilis, M. mexicana, M. micrantha, M. mollis, M. monoensis, M. montana, M. multicaulis, M. multiflora, M. nitens, M. nuda, M. oligosperma, M. oreophila, M. pachyrhiza, M. packardiae, M. paradoxensis, M. pectinata, M. perennis, M. polita, M. procera, M. pterosperma, M. puberula, M. pumila, M. ravenii, M. reflexa, M. reverchonii, M. rhizomata, M. rusbyi, M. saxicola, M. shultziorum, M. sivinskii, M. speciosa, M. springeri, M. strictissima, M. thompsonii, M. tiehmii, M. todiltoensis, M. torreyi, M. tricuspis, M. tridentata, M. uintahensis, M. veatchiana
Name authority Linnaeus: Sp. Pl. 1: 516. (1753) H. J. Thompson & J. E. Roberts: Phytologia 21: 284. (1971)
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