Psilostrophe gnaphalodes
Psilostrophe
dudweed
paper-daisy, paperflower
arachno-villous (gray to gray-green).
erect to spreading, branched from bases or throughout (not scapiform).
basal and cauline or all cauline; alternate; petiolate or sessile;
blades spatulate to oblanceolate or linear, margins usually entire (sometimes toothed or lobed on larger rosette leaves), faces densely to sparsely arachno-villous or ± strigillose, often gland-dotted as well.
(5–)10–25 mm.
5–6 mm.
cylindric to campanulate or obconic, 2–7 mm diam.
flat or convex, smooth or ± pitted (without setiform enations, sometimes gland-dotted), epaleate.
1–8, pistillate, fertile;
corollas yellow to orange (marcescent, spreading or reflexed in fruit).
5–9(–12).
5–25+, bisexual, fertile;
corollas yellow to orange, tubes shorter than narrowly cylindric throats, lobes 5, deltate (equal, papillate abaxially).
persistent, 5–12 in 1–2 series (erect in fruit, distinct, oblong to lanceolate, bases ± indurate).
in ± loose to crowded, corymbiform arrays.
radiate, usually in compact, corymbiform arrays or glomerulate clusters (borne singly in P. cooperi).
villous;
pappi of 4–5 lance-subulate scales 2–2.5 mm (scales ± villous abaxially and margins ± lacerate).
cylindric to clavate or obpyramidal, sometimes weakly obcompressed (ray), all striate-ribbed, usually glabrous, sometimes gland-dotted (villous in P. gnaphalodes, sometimes hirtellous in P. tagetina);
pappi of 4–8 ± oblong or elliptic to lanceolate or lance-subulate, entire (lacerate in P. gnaphalodes) scales (without prominent midribs).
(2–)3(–4);
laminae 4–6+ mm, spreading in fruit.
= 16.
= 32.
Psilostrophe gnaphalodes
Psilostrophe
Species 7 (6 in the flora).
My treatment of psilostrophes closely follows that by R. C. Brown (1978). Psilostrophe mexicana R. C. Brown is known from Chihuahua and Durango.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Subshrubs or shrubs; stems pannose (white); heads borne singly; peduncles 35–60(–80+) mm | P. cooperi |
1. Biennials or perennials; stems arachno-villous (gray to gray-green) or strigillose (greenish); heads in corymbiform arrays; peduncles 0.5–25(–50) mm | → 2 |
2. Stems ± strigillose, (greenish, sometimes ± villous in proximal axils); ray laminaereflexed in fruit | P. sparsiflora |
2. Stems mostly arachno-villous (gray to gray-green); ray laminae spreading in fruit | → 3 |
3. Involucres 7–9(–12) mm; disc florets (10–)12–15(–20); pappus scales oblong to ovate, 1.5–2 mm | P. bakeri |
3. Involucres 4–6(–8) mm; disc florets 5–8(–12); pappus scales elliptic or lanceolate to linear-subulate, 2–3+ mm | → 4 |
4. Cypselae villous | P. gnaphalodes |
4. Cypselae usually glabrous, sometimes hirtellous and/or gland-dotted | → 5 |
5. Peduncles (3–)12–20(–40) mm; ray laminae (5–)7–14+ mm | P. tagetina |
5. Peduncles (0.5–)1–3(–5+) mm; ray laminae 3–4(–6) mm | P. villosa |
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