Overview
Annuals or perennials, 10-20(-30+) cm . Stems prostrate to erect, usually branched ± throughout. Leaves cauline; opposite; petiolate [± sessile]; blades (usually 3-nerved) ovate to rhombic or lanceolate [linear to filiform], bases ± cuneate, margins entire or toothed, faces sparsely pilose to strigillose, glabrescent. Heads radiate or discoid [disciform], borne singly at tips of branches [corymbiform arrays]. Involucres ± hemispheric to ovoid, 3-6+ mm diam. Phyllaries pe
rsistent, 8-15+ in 1-3 series (distinct, ovate to linear, subequal or outer longer). Receptacles conic, paleate (paleae falling with fruit, ± navicular, membranous to scarious, each about equaling subtended floret). Ray florets 0 or 5-20+, pistillate, fertile; corollas yellow to orange [white or purplish] (laminae ovate to linear) [wanting]. Disc florets 25-100(-200+) bisexual, fertile; corollas yellow [orange], tubes shorter than campanulate throats, lobes 4-5, deltate. Cypselae 2-3-angled (peripheral) or strongly compressed, ellipsoid to obovoid (glabrous or ciliate on the 2-3 angles or ribs) ; pappi 0, or fragile, of 1-3 awnlike bristles. x = 13.
Species 30: s United States, Mexico, West Indies, Central America, South America; introduced in Asia, Africa, Pacific Islands, Australia.
Acmella pilosa R. K. Jansen has been reported as introduced in Florida (http://www.plantatlas.usf.edu) ; it differs from A. repens mainly by its more densely pilose stems and leaves and more truncate to cordate (versus cuneate) leaf bases.[1]
Taxonomy
The Genus Acmella is further organized into finer groupings including:
- Species: ZipcodeZoo has pages for 66 species, subspecies, varieties, forms, and cultivars in the Genus Acmella: A. alba · A. alba var. ecuadorensis · A. alpestris · A. bellidioides · A. biflora · A. brachyglossa · A. brasiliensis · A. buphthalmoides · A. caulirhiza · A. caulorrhiza · A. ciliata · A. darwinii · A. debilis · A. decumbens (Creeping Spotflower) · A. decumbens var. affinis · A. filipes · A. filipes var. cayensis · A. filipes var. parvifolia · A. fimbriata · A. flavicaulis · A. garcini · A. glaberrima · A. globosa · A. grandiflora · A. grandiflora var. brachyglossa · A. grandiflora var. discoides · A. grandiflora var. grandiflora · A. grisea · A. hirta · A. intermedia · A. iodiscaea (Maluco) · A. lanceolata · A. leptophylla · A. leucantha · A. linnaei · A. lundellii · A. mauritanica · A. mutisii · A. nudicaulis · A. nuttaliana · A. occidentalis · A. oleracea (Perennial Para Cress) · A. oleracea 'Peek-A-Boo' · A. oleraceae · A. oppositifolia (Opposite-Leaved Para Cress) · A. oppositifolia (Lam.) R.K.Jansen var. repens (Walt.) R.K.Jansen · A. oppositifolia var. repens (Oppositeleaf Spotflower) · A. paniculata (Paniculated Spot Flowers) · A. papposa · A. papposa var. macrophylla · A. parvifolia · A. pilosa (Hairy Spotflower) · A. poliolepidica · A. psilocarpa · A. pusilla (Dwarf Spotflower) · A. radicans · A. radicans var. debilis · A. ramosa · A. repens · A. serratifolia · A. sodiroi · A. spilanthoides · A. tenella · A. trilobata
Bibliography
- Jansen, R. K. 1985. The systematics of Acmella (Asteraceae-Heliantheae). Syst. Bot. Monogr. 8: 1-115.
Footnotes
- John L. Strother "Acmella". in Flora of North America Vol. 21 Page 64, 65, 67, 132. Oxford University Press. Online at EFloras.org.
Sources
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