Difference between revisions of "Mentzelia involucrata"
Proc. Amer. Acad. Arts 20: 367. 1885.
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Latest revision as of 18:28, 29 July 2020
Plants 7–35 (–45) cm. Basal leaves: petioles present or absent; blade lanceolate, to 10 (–16) cm; margins shallowly to deeply lobed, lobes acute. Cauline leaves: petioles absent; blade ovate to lanceolate, to 10 (–16) cm, base often cordate-clasping, margins deeply to shallowly lobed, lobes acute. Bracts white with green margins, conspicuous, concealing pedicel, ovary, and capsule. Flowers: petals white to pale-yellow, usually with orange veins, obovate, 13–65 mm, apex mucronate; stamens 4–26 mm, less than 1/2 petal length, all fertile, none petaloid (flowers appearing to have 5 petals); filaments ± monomorphic, linear, distally 2-lobed, lobes 0.5–2 mm; anther stalk shorter or longer than filament lobes; style 8–30 mm. Capsules cylindric to cupshaped, 14–25 (–30) × 5–10 mm, erect. Seeds usually constricted proximal to middle; seed-coat anticlinal cell-walls wavy. 2n = 18.
Phenology: Flowering Jan–May.
Habitat: Washes, fans, slopes, desert scrub.
Elevation: 50–900 m.
Distribution
![V12 708-distribution-map.jpg](/w/images/f/f3/V12_708-distribution-map.jpg)
Ariz., Calif., Mexico (Baja California), Mexico (Sonora)
Discussion
Mentzelia involucrata is easily distinguished from other species in sect. Bicuspidaria by its large white bracts, which are strikingly similar to those of M. congesta in sect. Trachyphytum. Phylogenetic studies show that these species are not closely related, suggesting a homoplasious origin of the characteristic (J. M. Brokaw and L. Hufford, 2010). Populations exhibiting petals longer than 3 cm have previously been called var. megalantha. However, a study by G. S. Daniels (1970) suggested that insufficient geographic and morphological discontinuities exist for recognition of varieties.
P. A. Munz (1974) mistakenly cited var. megalantha as Mentzelia involucrata subsp. megalantha I. M. Johnston, a name never validly published.
Selected References
None.
Lower Taxa
"not elongating" is not a number.