Addisonia 77 



(Plate 159) 



POINSETTIA HETEROPHYLLA 



Fire-on-the-mountain 



Native of the central and western United States 

 Family Euphorbia cea:^ Spurge Family 



Euphorbia heterophylla L. Sp. PI. 453. 1753. 



Poinsettia heterophylla Klotzsch & Garcke; Klotzsch, Monatsb. Akad. Berlin 

 1859: 253. 1859. 



An annual, bushy herb, one to four feet high, with a milky, acrid 

 juice. The stems are erect, green, glabrous, and bear many leaves 

 and red-blotched bracts subtending closely-clustered involucres. 

 The leaves are alternate, bright green, slender-petioled, and ex- 

 tremely variable in shape; the lower ones are ovate, wedge-shaped 

 at their bases, acuminate, with sinuate-dentate margins; the upper 

 ones are nearly as large, mostly fiddle-shaped, and variously 

 toothed, often red-blotched near the base. The bracts subtending 

 the clusters of involucres are small, lanceolate, acute, and with 

 showy bright red areas near their bases. The involucres, resembling 

 perianths but actually containing the reduced staminate and pistil- 

 late flowers, are in dense clusters, closely surrounded by the red 

 bracts ; they are green and cup-shaped and have four fimbriate lobes 

 with usually one rarely four small green glands, without petal-like 

 appendages, on the sinuses. The four stamens are short and thick, 

 with bright green anthers. The ovaries, on short stalks, bearing 

 three-parted spreading stigmas, quickly ripen into three-lobed 

 capsules containing three cream-colored tuberculate seeds. 



The fire-on-the-mountain, or annual poinsettia, as this spurge is 

 sometimes called, while lacking showy floral parts, has, in common 

 with our Christmas poinsettia, the conspicuous red markings, 

 although not of such vivid hue. It is a valuable summer-flowering 

 plant, a companion to our snow-on-the-mountain (plate 86), 

 which has white bracts. 



This plant was introduced into cultivation about 1885, through 

 American seedsmen. If cut back early in the season, it will make a 

 strong bush for summer color. Propagation is efi"ected by seeds 

 sown in the open ground in spring, or better by sowing the seeds in a 

 coldframe or greenhouse in March. The young plants should be 

 pinched back so they will branch freely and become stocky. 



