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(Last Modified On 6/18/2013)
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(Last Modified On 6/18/2013)
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Subspecific
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Chrysanthellum americanum var. integrifoliumn (Steetz) Alexander
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PlaceOfPublication
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N. Amer. Flora, ser. 2, 2: 148. 1955.
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Synonym
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Chrysanthellum integrifolium Steetz in Seem., Bot. Voy. Herald 160. 185.
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Description
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Small glabrate herbs; stems prostrate and ascending, to 20 cm long, sparingly branching, with a small tap root. Leaves oblanceolate, to 10 cm long and 2.5 cm wide, apically dentate and rounded to obtuse, mostly entire below, basally narrowed and the slender petiole not differentiated from the blade, slightly clasping the stem, pinnately veined mostly in the upper portion, often drying reticulate on both sides, glabrate, ?succulent. Inflorescence a solitary head; peduncle ascending, slender, glabrate, to 15 cm long, sometimes minutely puberulent at the apex, sometimes with one or two foliaceous or scalelike bracts along the length. Heads radiate; involucral bracts of 2 dissimilar forms, the outer- most 4-8, subulate, ca. 2 mm long and 0.5 mm wide, apically acute, basally enlarged into a (?succulent) boss, the innermost 13-18 bracts in 2 similar series, imbricate, 3-5 mm long, 1.5 mm wide, oblong, apically obtuse, drying reddish brown, indurate, the margins broad, hyaline, entire; receptacle depressed- hemispherical; paleas linear, drying dark-striate, exceeding the ovaries but mostly shorter than the filaments, nearly flat; ray florets ca. 18 in 2-3 series, ca. 9 mm long, the corolla yellow, 6-7 mm long with two prominent, puberulent, brownish-red longitudinal stripes, apically 2(3) -denticulate, the tube ca. 1 mm long, the style branches flattened, glabrous, the style with 2 vascular traces, basally minutely expanded, the ovary narrowly turbinate, laterally flattened, pubescent with weak, multicellular hairs, half enfolded by palealike bracts; disc florets ca. 13, ca. 4 mm long, the corolla campanulate with a short tube and 5 glabrous lobes, the lobes veinless, the anthers dark, 1 mm long, the appendages clear, deltoid, the style branches flattened, pilose ventrally and marginally, the style with 2 vascular traces, not basally expanded, the ovary oblong, compressed. Achene oblong, strongly flattened, 3 mm long, 1-2 mm wide, black with massive, light-colored wings; pappus wanting.
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Habit
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herbs
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Distribution
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grows in wet, sunny spots in lowland Panama.
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Note
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The wings of the achenes are larger and more massive relative to the flat, black central portion than in any other epappose species of Compositae in Panama. Variety integrifolium has entire or apically dentate leaves, while the typical var. americanum has dissected leaves with filiform segments. The heads of var. integrifolium are larger as well. Variety integrifolium is reported to have only one sort of achene, but this may not be true of all plants. Both varieties occur on Jamaica, the type locality for the species. The typical variety ranges across the Old and New World tropics, but var. integrifoliurn appears to be restricted to the Caribbean region.
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Distribution
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var. integrifoliurn appears to be restricted to the Caribbean region.
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Specimen
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CANAL ZONE: Fort Kobbe, Duke 3973 (MO). COCLE: LIanos, Penonome, Ebinger 1028 (MO). Between Aguadulce and Anton, 15-50 m, Woodson et al. 1220 (MO). HERRERA: Pese, ca. 50 m, Allen 811 (MO). PANAMA: Savanna near Rio Pacora and Chepo Hwy., Duke 5933 (MO). Sabana de Juan Corso near Chepo, 60-80 m, Pittier 4505 (MO).
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