Poinsettia pulcherrima (Willd. ex Klotzsch) Graham
A more or less erect sparingly-branched softly woody plant usually up to 2 m tall, sometimes taller, with a fleshy storage root in the seedling-stage. Stem-leaves alternate, long-petiolate, the petioles 2.5-5 cm long; blades elliptic-ovate to dentate-panduriform, 7-14 (-20) x 3-7 (-10) cm, obtusely acuminate at the apex, cuneate at the base, entire or irregularly crenate-serrate to repand-dentate, lateral nerves up to 20 pairs, subglabrous and dark green above, sparingly puberulous and paler beneath. Stipules sessile, glandular. Leaves of the pseudopleiochasium clustered, petiolate, the petioles 1-3 cm long; blades elliptic-oblanceolate, 5-13 x 1-3 cm, acutely long-acuminate at the apex, attenuate at the base, entire or subentire, lateral nerves c. 12 pairs, sparingly puberulous at first, later becoming subglabrous above, bright red or cream. Cyathia aggregated together in dense terminal basically triradiate pseudopleiochasia, 7-9 x 6-8 mm, borne on stout peduncles 2-6 mm long. Gland solitary, cupular, 4.5 mm across, yellowish. Fruit rounded-trilobate, c. 1.5 x 1.5 - 2 cm, smooth, glabrous. Styles connate at the base, 5 mm long, bipartite. Seeds ovoid, 10 x 8-9 mm, ± smooth, pale grey, ecarunculate.
Fl. Per: Jan: April.
Holotype: Mexico, Karwinsky in Hb. WILLD. No. 9259 (B-WILLD, missing).
Distribution: C. America from Mexico to Costa Rica. Now widely cultivated in the tropics and subtropics.