Family: Asteraceae
Leptorhynchos
Citation:
Less., Syn. Comp. 273 (1832).
Derivation: Greek leptos, slender; rhynchos, a snout; alluding to the beaked achenes of some species.
Synonymy: Rhytidanthe Benth. in Endl., Enum. Pl. Hügel 63 (1837); Doratolepis (Benth.) Schldl., Linnaea 20:593 (1847).
Common name: Buttons.
Description:
Annual or perennial herbs; vestiture of glandular and non-glandular short, long or woolly-cobwebby hairs; leaves cauline, alternate, sessile or with a sheathing base, entire.
Capitula solitary, terminal and on long peduncles bearing distant scarious bracts or in leafy corymbs, heterogamous, discoid; involucre campanulate, many-sedate, never radiating; involucral bracts graded in length, the innermost ones longest; outer bracts more or less sessile, largely scarious, translucent and white or stramineous; inner bracts herbaceous or subherbaceous, glandular-pubescent, with small erect scarious laminae; receptacle convex, naked, pitted; florets numerous, mostly bisexual and fertile, 5-merous, but a few of the outer ones female, 3- or 4-merous; corolla tubular, markedly dilated towards the limb, yellow or creamy-white, exceeding the involucre and overhanging it; anthers tailed at the base; style branches linear, with a truncate-papillose apex.
Achenes oblong, ellipsoid or fusiform, somewhat compressed, slightly contracted just below the summit or with a long slender or gradually contracted sterile beak, all similar; pappus uniseriate, of a few to many equal shortly connate bristles; bristles slender, barbellate, usually more strongly so towards the apex; pappus of female florets reduced.
Distribution:
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About 10 species, endemic to Australia, not reliably distinguished from some groups of species in Helichrysum and Waitzia.
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Biology:
No text
Key to Species:
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1. Involucral bracts ciliate, at least some bracts with cilia in length a third and up to 3 times as wide as the bracts |
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2. Lower leaves with a strongly sheathing base; tufted perennials |
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3. Leaves mostly 3-6 cm (but up to 14 cm) long and rarely more than 1 mm wide, linear, with revolute margins, often only the midrib visible beneath; pappus bristles 4 (rarely 7) |
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L. tenuifolius 5. |
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3. Leaves mostly 1-3 cm long, 1.5-5 mm wide, oblanceolate to narrowly so, with narrowly recurved margins; pappus bristles 8-12 |
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L. squamatus 4. |
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2. Lower leaves sessile at the base but not sheathing; tap-rooted annual or perennial herbs |
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4. Pappus bristles of bisexual florets 4 or fewer |
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5. Pappus bristles of bisexual florets 4, about equal to the corolla, barbellate in the upper half |
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L. tetrachaetus 6. |
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5. Pappus bristles of bisexual florets 1-3, only three-quarters as long as the corolla, stiffly plumose in the upper half |
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L. baileyi 1. |
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4. Pappus bristles of bisexual florets 5 or more |
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L. waitzia 7. |
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1. Involucral bracts entire or shallowly laciniate, not ciliate |
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6. Achenes tapering gradually into an indistinct beak, densely papillose towards the apex; florets creamy-white to pale-yellow; perennial |
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L. elongatus 2. |
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6. Achenes with a distinct long slender beak, glabrous towards the apex; florets bright-yellow; annual |
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L. scabrus 3. |
Author:
Prepared by L. Haegi
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