Thelesperma
greenthread
usually 1, erect, branched distally or ± throughout.
mostly basal, basal and cauline, or mostly cauline; mostly opposite (distal rarely alternate);
blades usually 1(–3)-pinnately lobed (ultimate lobes oblanceolate to filiform), faces usually glabrous, rarely hairy.
hemispheric to urceolate, 4–15+ mm diam.
flat to convex, paleate;
paleae falling, (whitish with red-brown striae, each ± appressed to abaxial face of subtended cypsela), obovate to oblong, scarious.
0 or ca. 8, neuter;
corollas yellow or red-brown, or bicolored (yellow and red-brown).
20–100+, bisexual, fertile;
corollas yellow (with red-brown nerves) or red-brown, either with throats equal to or longer than 5, ± deltate, ± equal lobes, or with throats shorter than 5, ± lance-linear, ± unequal lobes (in either form, the abaxial sinus usually ± deeper than others).
5–8 in ± 2 series, persistent, connate 1/5–7/8+ their lengths, lance-ovate to ovate, ± equal, ± leathery to membranous, margins (of distinct apices) scarious.
of 3–8+ distinct, usually spreading or reflexed, usually linear to subulate, herbaceous bractlets.
radiate or discoid, borne singly or in loose, corymbiform arrays.
(dark red-brown or stramineous) outer often arcuate, shorter, inner more columnar, usually some or all ± obcompressed (each usually shed together with its subtending palea), faces smooth or papillate to tuberculate or verrucate, margins sometimes ± winged;
pappi 0, or persistent, of 2 retrorsely ciliate, subulate scales or awns.
= 12.
Thelesperma
Species 10+ (9 in the flora).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Throats of disc corollas equal to or longer than lobes; pappi usually 0, rarely of 2 awns 0.1–0.3(–0.5) mm | → 2 |
1. Throats of disc corollas shorter than lobes; pappi usually of 2 awns or scales (0.5–)1–3 mm, rarely 0 | → 4 |
2. Cauline leaves ± scattered over proximal 3/4+ of plant heights, internodes mostly 45–95 mm | T. simplicifolium |
2. Cauline leaves ± crowded over proximal 1/4–1/2 of plant heights, internodes mostly 5–25+ mm or 1–5(–35) mm | → 3 |
3. Leaf lobes mostly linear to filiform, 5–25(–45+) × 0.5(–1) mm; cypselae 2–3 mm | T. longipes |
3. Leaf lobes mostly oblanceolate to linear, (5–)10–35(–45+) × (1–)2–3(–5) mm; cypselae 5–7 mm | T. subnudum |
4. Perennials (sometimes flowering first year); calyculi of 3–5+, ovate to oblong bractlets 1–3 mm; ray florets 0, or 8, laminae 4–8(–12+) mm; cypselae (4–)5–8 mm | → 5 |
4. Annuals (sometimes persisting); calyculi of 5–9, linear to narrowly triangular bractlets (2–)4–8+ mm; ray florets 8, laminae 10–20+ mm; cypselae 3.5–5.5+ mm | → 6 |
5. Plants 10–30(–50) cm; ray florets usually 8, rarely 0; disc corollas red-brown | T. ambiguum |
5. Plants (20–)30–80+ cm; ray florets 0; disc corollas yellow | T. megapotamicum |
6. Ray laminae proximally to wholly red-brown to purplish, or each with a proximal red-brown spot; disc corollas red-brown to purplish | → 7 |
6. Ray laminae yellow to golden (rarely proximally suffused with red-brown); disc corollas yellow or red-brown | → 8 |
7. Calyculi of 5–6(–9), linear to narrowly triangular bractlets (margins hispido-ciliate); cypselae 3.5–4 mm | T. burridgeanum |
7. Calyculi of 6–7+, narrowly triangular bractlets (margins not ciliate); cypselae 5–5.5+ mm | T. nuecense |
8. Plants 30–70(–120+) cm; cauline leaves ± scattered over proximal 9/10 of plant heights, internodes 35–100+ mm; disc corollas yellow, often with brown nerves | T. flavodiscum |
8. Plants 10–40(–70+) cm; cauline leaves crowded to ± scattered over proximal 1/2–3/4+ of plant heights, internodes mostly 10–35(–50+ mm); disc corollas red-brown or yellow with red-brown nerves | T. filifolium |
CA
OR
Flora NW
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
