Eucnide bartonioides
Eucnide
yellow rocknettle, yellow stingbush
pretty nettle, rock-nettle, stingbush
usually erect or spreading, rarely prostrate or pendent on cliffs.
blade shallowly to prominently lobed.
cauline;
petiole present;
blade ovate, lobed or unlobed, margins crenate or dentate.
dichasia and monochasia [solitary flowers];
peduncle inconspicuous [conspicuous].
(fruiting) 3–35+ cm, frequently recurved.
elongating in fruit.
radially symmetric or slightly bilaterally symmetric through upward curvature of stamen filaments;
corolla funnelform, petals connate to 3 mm, 1-colored, yellow, spatulate, 10–55[–58] mm;
stamens 15–150+, inserted at base of corolla, exserted, spreading away from style;
filaments 13–60 mm, longer than anthers.
hypanthium completely adnate to ovary;
perianth whorls differentiated;
sepals green, distinct, lanceolate, straplike, or narrowly ovate, shorter than petals;
petals white, green, or yellow [reddish orange], connate proximally to 1/2+ length, spatulate or ovate, spreading or erect (then corolla essentially tubular) [erect proximally, divaricate distally (corolla salverform)], glabrous except apices sparsely hairy;
nectary distal on ovary;
stamens 15–150+, exserted or included;
filaments monomorphic, filiform, longer or shorter than anthers;
anthers without distal connective extension;
staminodes absent;
pistil 5-carpellate, placentae parietal;
stigma lingulate, 5-lobed, papillate.
capsules, dehiscing by apical valves [splitting longitudinally], cup-shaped, straight;
sepals persistent.
many, cylindric to ovoid, not dorsiventrally flattened, to 1 mm, not winged.
= 21.
Eucnide bartonioides
Eucnide
Varieties 2 (2 in the flora).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Species 14 (4 in the flora).
Eucnide was placed in subfam. Mentzelioideae by I. Urban and E. Gilg (1900), Gilg (1925b), and H. J. Thompson and W. R. Ernst (1967); however, this subfamily is paraphyletic. Eucnide has been placed in molecular phylogenetic studies as sister to the rest of Loasaceae (L. Hufford et al. 2003).
Three sections of Eucnide were recognized by H. J. Thompson and W. R. Ernst (1967). Section Mentzeliopsis H. J. Thompson & W. R. Ernst, consisting only of E. urens, was distinguished on the basis of its floral architecture in which all stamens are shorter than the style and not exserted beyond the corolla. The numerous stamens of E. urens are also tightly positioned around the style. Section Sympetaleia (A. Gray) H. J. Thompson & W. R. Ernst consists of three species that are endemic to the Baja California Peninsula and surrounding islands, except for E. rupestris, which has a distribution that extends into extreme southern California and southwestern Arizona and to Sinaloa and Sonora, Mexico. Species of sect. Sympetaleia have stamens with monothecate, bisporangiate anthers in contrast to other members of the genus, which have more conventional bithecate, tetrasporangiate anthers. All other species of Eucnide were placed in sect. Eucnide by Thompson and Ernst.
Among the North American species of Eucnide, E. urens is the only species found in the Mojave Desert, where it is centered (H. J. Thompson and W. R. Ernst 1967). The other North American species are found in the Chihuahuan and Sonoran deserts and in adjacent areas. All species are found in similar cliff or rocky slope habitats (uncommonly in arroyos and washes). Some species, such as E. bartonioides, have fruit pedicels that are negatively phototropic and elongate extensively, which appear to be adaptations for dispersal on cliffs (Thompson and Ernst).
Most species of Eucnide are self-pollinating (H. J. Thompson and W. R. Ernst 1967), although they generally have some spatial separation between the stigmas and anthers soon after the flowers open that allows for cross-pollination (L. Hufford 1988). Only taxa with the largest flowers, such as E. bartonioides var. bartonioides (possibly pollinated by hawk moths) and E. urens (pollinated by the melittid bee, Hesperaster laticeps), appear to be strictly outcrossing (Thompson and Ernst).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Petals 30–55 mm; stamens (55–)70–150+, filaments 30–60 mm. | var. bartonioides |
1. Petals 10–25 mm; stamens 15–70, filaments 13–30(–35) mm. | var. edwardsiana |
1. Corollas essentially tubular, petals to 15 mm, connate to 9 mm, 2-colored, yellow to brown basally, green distally; stamen filaments less than 5 mm, inserted in upper portion of corolla tube. | E. rupestris |
1. Corollas funnelform or rotate, petals 10–55 mm, connate to 5 mm, 1-colored, white, cream, or yellow; stamen filaments 10–60 mm, inserted at base of corolla. | → 2 |
2. Petals white to cream; stamens included, most aggregated around style, only longer, outermost stamens spreading away from style. | E. urens |
2. Petals yellow; stamens exserted, spreading away from style. | → 3 |
3. Corollas funnelform; filaments 13–60 mm. | E. bartonioides |
3. Corollas rotate; filaments 7–16 mm. | E. lobata |
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