Ageratina adenophora (Spreng.) R.M.King & H.Rob.

Family Description

Annual, biennial or perennial herbs, sometimes shrubs, rarely trees, tissues sometimes containing milky sap, glabrous, pubescent, tomentose, spinous or variously sessile- or stipitate-glandular. Leaves alternate or sometimes opposite, exstipulate (but sometimes with stipuliform appendages), entire, toothed, lobed or variously dissected. Individual flowers usually numerous, aggregated and ± sessile (briefly immersed to very shortly stipitate) on a common receptacle and surrunded by an involucre of 1-many series of phyllaries (involucral bracts),the whole comprising a capitulum; phyllaries free, rarely connate; capitula solitary to very many, rarely agreegrated into secondary capitulum-like glomerules.Receptable sometimes bearing paleae (scales), hairs or bristles.Flowers (florets)epigynous, bisexual, female, m ale(at least functionally so) or neuter (sterile). Calyx absent, often replaced on apex of ovary by a pappus of 1 or more series of bristles and / orscales. Corolla gamopetalous, tabular throughout or dilated or 1(-2)-lipped above,variously truncate or 1-5-toothed at apex (appices); rarely corolla absent. Stamens (1-)5, epipetalous, filaments free anthers laterally connate into a cylinder around style (free in one species). Ovary inferior, 1-celled with one basal ovule; style usually divided above into two branches, sometimes entire on male flowers, emerging through anther cylinder, first collecting and exposing pollen,later exposing stigmatic surfaces if bisexual. Fruit an achene (cypsela) usually bearing a persistent or deciduous pappus; pappus sessile or borne on a beak(rostrum).

Genus Description

Herbaceous perennials subshrubs or shrubs partly sessile or stipitate glandular.Leaves opposite simple trullate to obovate petiolate subentire to coarsely toothed.Capitula in corymbs, 5-8 or 50-60 flowered, discoid.Involucres white tubular campanulate.Style branches linear exserted obtuse. Achenes narrowly oblong blackish pale and empty at base, 5 angled or ribbed; pappus of 1 series of glandular. corollas narrowly oblong blackish, pale and empty at base, 5 angle or ribbed; pappus of 1 series of capillary bristles, subequal to corolla, white.

Species description

Herb and subshrub, 0.4-2m; stems ± erect branched purplish(-brown), densely glandular pubescent.Leaves trullate, blades 2-7 x 1.5-5.5cm, acuminate obtuse and 3 veined at base, coarsely(serrate-) dentate, subglabrous above, glandular pubescent beneath; petioles slender 0.8-3cm. Capitula campanulate, c 50 x 60 flowered in dense terminal and axillary corymbs.Involucres 3 seriate 4mm diameter; outer phyllaries few, reduced; inner ones oblanceolate; 4.3-5 x 0.7-1mm, acuminate stipulate glandular, 3 veined on back.Corollas 3.5-4mm. Achenes 1.5-2mm, glabrous; pappus bristles c 10-12 caducous.