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tumblemustard

spreading thelypodiopsis

Habit Annuals, biennials, or, rarely, perennials; not scapose; glabrous or pubescent. Annuals or biennials; pubescent proximally, glabrate distally.
Stems

(simple or few to several from base), erect [ascending, decumbent], branched basally and/or distally, (glabrous or pubescent).

usually branched distally, rarely unbranched, 2–8.5(–10) dm, (often densely pubescent proximally, trichomes flat, crisped).

Leaves

basal and cauline;

petiolate or sessile;

basal (soon caducous), rosulate or not, petiolate, blade margins entire or dentate;

cauline sessile, blade (base auriculate, sagittate, or amplexicaul), margins entire or dentate.

Basal leaves

(soon withered);

not rosulate;

blade oblong, 2–10 cm × 10–30 mm, margins entire or dentate, (surfaces glabrous or sparsely pubescent).

Cauline leaves

sessile;

blade (proximalmost) oblong or (distal) oblong to ovate, base auriculate to amplexicaul, margins usually entire or dentate (rarely dentate distally).

Racemes

(corymbose, dense or lax), considerably [slightly] elongated in fruit.

dense.

Flowers

sepals (equal), usually erect, sometimes ascending or spreading, rarely reflexed, oblong, lateral pair not saccate basally;

petals (erect basally), usually white, lavender, or purple, rarely yellow, oblanceolate, oblong, spatulate, or obovate, (margins rarely crisped), claws differentiated or not from blade, (apex rounded);

stamens tetradynamous, (exserted);

filaments distinct;

anthers usually linear, sometimes ovate or oblong (apically coiled);

nectar glands confluent, subtending bases of stamens.

sepals (calyx often urceolate), erect, yellowish, 3.5–5.5 × 1.5–2 mm, (sparsely pubescent);

petals yellow, oblong, 6.5–9(–10) × 1–1.7 mm, (margins crisped), claw 3.5–5 mm (to 2 mm wide);

median filament pairs 4–5 mm;

anthers linear, 2.5–3.5 mm;

gynophore (stout), 0.5–1.5 mm.

Fruiting pedicels

erect to ascending or divaricate, slender.

divaricate-ascending to spreading, straight, (slender), 6.5–14(–21) mm, (glabrous or pubescent).

Fruits

stipitate, linear, torulose or smooth, terete;

valves each with prominent midvein, usually glabrous, rarely pilose;

replum rounded;

septum complete;

ovules 20–114 per ovary;

style distinct, (cylindrical or subclavate to clavate);

stigma capitate, usually strongly 2-lobed, rarely entire, (lobes opposite replum).

suberect to divaricate-ascending or spreading, straight, slightly torulose, 4–8(–9.5) cm × 1.2–1.7 mm; (valves sparsely pubescent at least when immature);

ovules 70–94 per ovary;

style subclavate, 0.7–2 mm;

stigma 2-lobed.

Seeds

uniseriate, plump, not winged, oblong;

seed coat (minutely reticulate), not mucilaginous when wetted;

cotyledons incumbent or obliquely so.

1–1.7 × 0.7–1 mm.

x

= 10, 11.

2n

= 22.

Thelypodiopsis

Thelypodiopsis divaricata

Phenology Flowering Apr–Jun.
Habitat Rocky knolls, sandy or clay grounds in juniper and shrub communities
Elevation 1200-2100 m (3900-6900 ft)
Distribution
from USDA
w United States; n Mexico
[BONAP county map]
from FNA
UT
[BONAP county map]
Discussion

Species 10 (9 in the flora).

As recognized by R. C. Rollins (1982b, 1993), Thelypodiopsis was artificially delimited, and no single characteristic or combination of characteristics reliably distinguished it from related genera. Rollins’s circumscription was so broad that it included species of Dryopetalon and Romanschulzia O. E. Schulz.

Of the nine species of Thelypodiopsis that occur in the flora area, three (T. purpusii, T. shinnersii, and T. vaseyi) are quite anomalous and, together with the Mexican T. versicolor (Brandegee) Rollins (Coahuila, San Luis Potosí), eventually may be excluded from the genus. Unlike the other six species, these three have entire or obscurely (versus prominently) 2-lobed stigmas, oblong or ovate anthers 0.5–1 mm (versus linear and 2.5–4 mm), and petal claws obscurely (versus strongly) differentiated from blades. They are here retained in the genus only tentatively and currently are being subjected to detailed molecular and morphological studies, along with Mexican, Central American, and South American taxa.

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

Thelypodiopsis divaricata is known from Carbon, Emery, Garfield, Grand, Kane, San Juan, and Wayne counties.

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

Key
1. Anthers ovate or ovate-oblong, 0.5-1 mm; stigmas entire or obscurely 2-lobed; petal claws 0-3 mm
→ 2
1. Anthers linear, 2.5-4 mm; stigmas 2-lobed; petal claws 3.5-8 mm
→ 4
2. Cauline leaf blades: proximalmost with pinnatifid to sinuate-dentate margins, distal ones with subamplexicaul or auriculate bases.
T. purpusii
2. Cauline leaf blades: proximalmost usually with entire or repand margins, rarely denticulate, distal ones with auriculate bases
→ 3
3. Proximalmost cauline leaf blades pandurate to broadly obovate; sepals erect; fruits 3.2-7.5 cm; ovules 60-102 per ovary.
T. shinnersii
3. Proximalmost cauline leaf blades oblong to lanceolate or oblanceolate; sepals spreading; fruits 1.5-2.5 cm; ovules 20-32 per ovary.
T. vaseyi
4. Gynophores slender, 2-6(-9.5) mm
→ 5
4. Gynophores stout, 0.2-1.5 mm
→ 7
5. Sepals yellow, spreading to reflexed; petals yellow.
T. aurea
5. Sepals purple, erect; petals usually purple or lavender, rarely white
→ 6
6. Stems glabrous basally; petals 10-14 mm; fruiting pedicels 6-9 mm; styles stout, 0.3-1 mm.
T. ambigua
6. Stems pilose basally; petals 14-17 mm; fruiting pedicels 7-20 mm; styles slender, 2-3 mm.
T. juniperorum
7. Sepals yellowish; petals yellow, 1-1.7 mm wide, margins crisped.
T. divaricata
7. Sepals purplish, lavender, greenish, or white; petals purple, lavender, or white, 3-5 mm wide, margins not crisped
→ 8
8. Proximal portions of stems and abaxial leaf surfaces often pilose; fruits not tortuous; styles often clavate.
T. elegans
8. Proximal portions of stems and abaxial leaf surfaces usually glabrous, rarely sparsely pubescent; fruits tortuous; styles cylindrical.
T. vermicularis
Source FNA vol. 7, p. 723. Author: Ihsan A. Al-Shehbaz. FNA vol. 7, p. 725.
Parent taxa Brassicaceae > tribe Thelypodieae Brassicaceae > tribe Thelypodieae > Thelypodiopsis
Sibling taxa
T. ambigua, T. aurea, T. elegans, T. juniperorum, T. purpusii, T. shinnersii, T. vaseyi, T. vermicularis
Subordinate taxa
T. ambigua, T. aurea, T. divaricata, T. elegans, T. juniperorum, T. purpusii, T. shinnersii, T. vaseyi, T. vermicularis
Synonyms Caulanthus divaricatus
Name authority Rydberg: Bull. Torrey Bot. Club 34: 432. (1907) (Rollins) S. L. Welsh & Reveal: Great Basin Naturalist 37: 355. (1978)
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