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Jones stickleaf, Jones' blazing star

cluster blazing star, congested blazingstar, flower baskets, united blazingstar

Habit Plants candelabra-form, 20–40(–50) cm. Plants wandlike or candelabra-form, 7–40(–50) cm.
Basal leaves

persisting;

petiole present or absent;

blade linear-lanceolate to linear, margins deeply lobed to dentate.

persisting;

petiole present or absent;

blade linear-lanceolate to linear, margins usually deeply to shallowly lobed, rarely entire.

Cauline leaves

petiole absent;

blade ovate-lanceolate to linear, to 15 cm, margins deeply to shallowly lobed or entire.

petiole present or absent (proximal leaves), absent (distal leaves);

blade linear-lanceolate to linear (proximal leaves), ovate-lanceolate (distal leaves), to 9 cm, margins deeply to shallowly lobed or entire.

Bracts

green, ovate to lanceolate, 3.7–5.9 × 0.8–3.9 mm, width 1/8–2/3 length, not concealing capsule, margins entire.

mostly white with green margins, conspicuous and showy, outer broadly ovate, inner obovate, outer 7–14.7 × 4.2–10.4 mm, inner 4.1–5.8 × 2.7–3.5 mm, width 1/2–7/8 length, concealing capsule, margins usually deeply 3–9-lobed to toothed, rarely entire.

Flowers

sepals (2–)4–8(–10) mm;

petals yellow to orange proximally, yellow distally, (6–)8–22 mm, apex acute to rounded;

stamens 20+, 3–10 mm, filaments monomorphic, filiform, unlobed;

styles 4–10 mm.

sepals 1–4 mm;

petals orange proximally, pale yellow to yellow distally, 2–8(–10) mm, apex retuse;

stamens 20–40, 1.5–5 mm, filaments monomorphic, filiform, unlobed;

styles 1.5–5 mm.

Capsules

clavate, 15–38 × 2–4 mm, axillary curved to 180° or S-shaped at maturity, usually inconspicuously longitudinally ribbed.

cylindric or clavate, 5–12 × 2–3 mm, axillary curved to 10° at maturity, usually inconspicuously longitudinally ribbed.

Seeds

15–30, in 2+ rows distal to mid fruit, tan, dark-mottled, usually irregularly polygonal, occasionally triangular prisms proximal to mid fruit, surface tuberculate under 10x magnification; recurved flap over hilum absent;

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

10–25, in 2+ rows distal to mid fruit, tan, dark-mottled or not, irregularly polygonal, surface tessellate 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

= 36, 54.

= 18.

Mentzelia jonesii

Mentzelia congesta

Phenology Flowering Mar–May. Flowering May–Jul.
Habitat Sandy to rocky washes, fans, or flats, creosote-bush scrub, Joshua-tree or saguaro woodlands. Disturbed slopes, sagebrush scrub, pinyon/juniper woodlands, pine forests.
Elevation 200–1500 m. (700–4900 ft.) 1200–2700 m. (3900–8900 ft.)
Distribution
from FNA
AZ; CA; NV; UT
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; ID; NV; OR
[WildflowerSearch map]
[BONAP county map]
Discussion

Mentzelia jonesii is widespread throughout southeastern California and western and southern Arizona. However, tetraploid populations have been found only in California and far northwestern Arizona. Hexaploids in California have previously been called M. californica. The ranges of M. jonesii and the diploid, M. nitens, overlap in southern Inyo County, California, and these species are difficult to distinguish morphologically without mature seeds; sepal and petal lengths, which have sometimes been used to distinguish them, overlap completely.

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

Mentzelia congesta is easily distinguished from other species in sect. Trachyphytum by its large, mostly white bracts. However, the bracts of M. congesta are strikingly similar to those of M. involucrata in sect. Bicuspidaria (see discussion under 53. M. involucrata). Phylogenetic studies suggest that the genome of M. congesta is present in more than half of the polyploid taxa in sect. Trachyphytum, including all species that exhibit bracts with partially white bases (J. M. Brokaw and L. Hufford 2010b).

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

Source FNA vol. 12, p. 537. FNA vol. 12, p. 535.
Parent taxa Loasaceae > Mentzelia > sect. Trachyphytum Loasaceae > Mentzelia > sect. Trachyphytum
Sibling taxa
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. 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. 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
Synonyms M. albicaulis var. jonesii, M. californica, M. nitens var. jonesii Acrolasia davidsoniana, M. congesta var. davidsoniana
Name authority (Urban & Gilg) H. J. Thompson & J. E. Roberts: Phytologia 21: 282. (1971) Torrey & A. Gray: Fl. N. Amer. 1: 534. (1840)
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