Sub- division: Angiospermae
Sub- class: Gamopetalae.
Family: Compositae (Asteraceae).
Herbs, few trees but climbers are rare.
Tap-root, branched and fibrous.
Soft, erect or prostrate, rarely climbers, sometimes woody, usually hairy with milky latex.
Radial or alternate, rarely opposite or whorled, exstipulate, mostly simple, smooth, hairy or rough; oil-ducts and latex present in some.
Am head or capitulum, consisting of a few or large number of sessile flower (ray and disc florets), closely grouped on a common disc-like, conical or cylindrical axil. The capitulum may be arranged in racemes, panicles, spikes, etc.
Reduced to a low ring or a fringe of scaly, bristly or hairy appendage on the rim of the floral axis and often persist on the ripe fruit, superior.
Sympetalous, 5-lobed or 6-cleft, actinomorphic (in disc-florets) or zygomorphic or ligulate (in ray- florets).
Stamens 5, epipetalous, filaments separate, anthers usually united to form a tube around the style, dehiscence introse, and superior.
Carpels 2, syncarpous; ovary inferior, Unilocular, with one basal ovule; style, simple; stigma bifid.
Achenial, cypsela bearing the persistent calyx as tuft of papas scales or bristles.
Helianthus Annus (Sunflower):
Tap-root, branched, fibrous.
Erect, herbaceous above, woody below, cylindrical, glabrous, branched.
Cauline and ramal, petiolate, exstipulate, simple, ovate, serrate, acute, unicostate and reticulate.
A head or capitulum consisting of two kinds of flowers, the disc florets, bisexual and tubular
Bractate, sessile, incomplete, irregular, zygomorphic, ligulate, pistillate or neuter epigyonous.
Absent or represented by 2-3 or more small scale, superior.
Yellow, gamopetalous a short basal tube and large flat strap shaped limb with 2-3 teeth which indicate the number of petals, superior.
Bractate, sessile, incomplete, regular, tubular, actinomorphic, hermaphrodite, epigynous.
Reduced, modified into 2-3 or more scales, superior.
Fie, gamopetalous, tubular, toothed, 5- teeth, superior.
Fie, epipetalous, filaments free short alternating with the petals; anther syngenesious, introse, superior.
Bicarpellary syncarpous; ovary inferior, Unilocular with a single basal ovule; style long; stigma bifid.