Osmadenia tenella |
Osmadenia |
|
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false rosinweed, osmadenia |
osmadenia |
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Habit | Annuals, 5–40 cm (self-incompatible; herbage strongly scented). | |
Stems | erect (branched, branchlets relatively many, commonly spreading, threadlike, densely glandular, scabrous to shaggy-hairy). |
|
Leaves | (proximal) 1–3(–5) cm, smaller distally. |
mostly cauline; alternate; sessile; blades linear, margins entire, faces hispidulous and glandular (proximally ± ciliate or shaggy-hairy). |
Involucres | ovoid, 2–4 mm diam. |
|
Receptacles | flat, glabrous, paleate (paleae persistent, in 1 series between rays and discs, connate, forming cups, distinct apices acute, often apiculate). |
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Ray florets/ |
tubes ca. 2.5 mm, laminae ca. 4 mm. |
3–5, pistillate, fertile; corollas wholly or mostly white (laminae 3-lobed, lobes sometimes each with prominent medial red blotch, overall often fading reddish, sinuses ± equaling laminae). |
Disc florets/ |
3–5 mm, lobes ± hirsute. |
3–10, bisexual, fertile; corollas usually wholly white, sometimes lobes each with prominent medial red blotch or reddish overall, tubes shorter than throats, lobes 5, deltate (anthers ± dark purple; styles glabrous proximal to branches). |
Phyllaries | 3.5–6.5 mm (paleae 4–6 mm) ± strigillose, strongly glandular, abaxial faces bristly, shaggy-hairy, especially margins and apices. |
falling, 3–5 in 1 series (each partly enveloping a ray cypsela, apices acute to attenuate). |
Heads | radiate, in loose, cymiform arrays. |
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Cypselae | (rays) 1.8–2.7 mm, beaks 0.3 mm, or (discs) 2–2.5 mm; pappi of scales 4–6 mm plus scales ca. 1 mm. |
(rays) ± obcompressed (± 3-angled, abaxial sides usually broadly 2-faced, angles between those faces usually 90+°, adaxial sides nearly flat), apices beaked, beaks off center, faces rugose, glabrous; or (discs) narrowly clavate, appressed-hairy; pappi (rays) 0, or (discs) of 4–5 lance-attenuate to aristate scales alternating with 4–5 shorter, ± fimbriate scales. |
Peduncular | bracts 4–7, narrowly lanceolate, 4–8 mm. |
bracts with tack-glands 0 (strigillose, strongly glandular, margins often proximally pectinate, ciliate). |
x | = 9. |
|
2n | = 18. |
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Osmadenia tenella |
Osmadenia |
|
Phenology | Flowering spring–summer. | |
Habitat | Barren, often rocky, exposed hillsides, canyons, chaparral, woodlands | |
Elevation | 10–600(–1200) m (0–2000(–3900) ft) | |
Distribution |
CA; Mexico (Baja California)
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CA; nw Mexico |
Discussion | Species 1. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 21, p. 269. | FNA vol. 21, p. 269. |
Parent taxa | Asteraceae > tribe Heliantheae > subtribe Madiinae > Osmadenia | Asteraceae > tribe Heliantheae > subtribe Madiinae |
Subordinate taxa | ||
Synonyms | Calycadenia tenella | |
Name authority | Nuttall: Trans. Amer. Philos. Soc., n. s. 7: 392. (1841) | Nuttall: Trans. Amer. Philos. Soc., n. s. 7: 391. (1841) |
Web links |