X 



XANTHlSMA (Greek, dyed yellow, referring to the 

 color of the Us. ). Compositir. A genus of only one spe- 

 cies, a summer-blooming, yellow-flowered composite with 

 heads 1-lK in. across, composed of a small disk and 

 about 20 rather slender rays. This plant is known to 

 flower-seed catalogues as Centattridium Drunimondii. 

 In cultivation the plant is treated like a hardy annual, 

 the seed being sown in the open border early in spring. 



Generic characters: fls. all fertile: akenes "top-shaped, 

 4-5-ribbed or angled; pappus persistent, composed of 

 10 or 12 rigid bristles which are minutely scabrous 

 above, gradually chaffy-dilated towards the base, and 

 longer than the disk-corolla, as many more one-half 

 shorter, and usually 5 still smaller and shorter external 

 ones. 



Tez&num, DC. {Centauridiiim Driimmondii. Torr. & 

 Gray). Fig. 2752. Nearly glabrous biennial or annual, 

 1-4 ft. high: Ivs. narrowly oblong to lanceolate; stem- 

 Ivs. entire or with a few teeth toward the apex: fls. at- 

 taining a diam. of 2 in. even in the wild. ^ff_ jj, 



XANTHOCfiBAS (Greek, lanthos, yellow, and keras, 

 horn, alluding to the yellow horn-like processes of the 

 disc). Utipiiiddcew. Ornamental deciduous shrub or 

 small tree with alternate, odd-pinnate Ivs., showy white 

 fls. in terminal and axillary racemes, appearing with the 

 leaves in spring on last year's branches. The large 

 greenish fruits are similar to those of the buckeye. X. 

 sorbifolia, the only species, is hardy as far north as 

 Mass., and is a very handsome shrub well suited for 

 solitary planting on the lawn. The dark green, glossy 

 foliage is not attacked by insects and retains its bright 

 color until frost sets in. The flowers are very showy 

 and appear even on small plants. Xanthoceras is also 

 sometimes used for forcing. It is not very particular as 

 to soil. A porous, loamy soil and a sunny position seem 

 to suit it best. Prop, by seeds, stratified and sown in 

 spring, and by root-cuttings, which succeed best with 

 moderate bottom-heat. A monotypic genus from N. 

 China, allied to Ungnadia and Koelreuteria: fls, polyga- 

 mous, the upper ones of the terminal raceme pistillate, 

 the lower ones staminate, those of the lateral racemes 

 staminate, with rarely a few pistillate ones at the apex; 

 sepals and petals 5; disc with 4 suberect cylindric horns 

 about half as long as stamens; stamens 8: ovary su- 

 perior, 3-loculed, with a rather short, thick style: fr. a 

 capsule, with thick walls dehiscent into 3 valves, each 

 locule with several globose, dark brown seeds. 



Borbif61ia, Bunge. Figs. 2753, 2754. Shrub or small 

 tree, attaining 15 ft.,wlth rather stout upright branches, 

 glabrous: Ivs. 6-12 in. long; Ifts. 9-17, usually oppo- 

 site, sessile, narrow-elliptic to lanceolate, sharply ser- 

 rate, dark green above, paler beneath, 1-2 in. long: ra- 

 cemes 6-10 in. long: fls. on slender pedicels, white, 

 about % in. across, each petal with a blotch at the base 

 changing from yellow to red: fr. green, 1J^-2K in. long; 

 seeds % in. across. May. N. China. B.M. 6923. F.S. 

 18:1899. R.H. 1872:290; 1898, p. 356. Gn. 8, p. 524 (col. 

 pi. not numbered); 34, p. 372; 50, p. 227. G.C. II. 

 26:205; 111.2:274.275; 11:533; 17:197. G.F. 6:285. A.P. 

 3:109; 12:36. A.G. 18:357. Gng. 2:292-293; 3:289. 

 Mn. 1, p. 27. M.D.G. 1900:592, 593. I. H. 24:295. 



Alfred Rehdee. 



XANTHOBBHCEA (Greek, yellow flow, referring to 

 the resin which exudes from the trunks). JuncAcea. The 

 "Grass Trees," "Grass Gums" or "Black Boys," which 

 form a conspicuous feature of the Australian landscape, 

 are among those strange members of the rush family 

 that have a decided trunk or caudex. The Grass Trees 

 often have a trunk 2 or 3 feet high, surmounted by a 

 dense, symmetrical crown of foliage, composed of a 

 multitude of brittle, linear leaves 2-4 ft. long which 

 spread or curve gracefully in all directions. From the 

 center of this tuft of leaves arises a solitary, sceptre- 

 like flower-stalk, terminating in a dense cylindrical spike 



of numerous, closely packed greenish flowers. These 

 picturesque desert plants are well worth trial in the 

 warmer and more arid regions of the U. S. The trunk 

 varies from almost nothing in some species to 15 ft. in 

 the case of aged specimens of A'. Preissii. The tall and 

 palm-like trunks are thickly covered with the bases of 

 the old dead leaves, which are cemented together by the 



2752. XanthismaTcxanumCXK). 



black or yellow resinous gum that flows freely from the 

 stems. In Australia the trunks are often charred and 

 discolored by bush fires. The following species have 

 been offered in southern Fla. and southern Calif., but 

 are practically unknown to cultivation in this country. 

 All the species are long-lived perennials native to dry 

 and rocky places. They are said to thrive in a com- 

 post of peat and loam and to be propagated by 

 offsets. X. Preissii seems to be the most desirable 



genus 



species of Australi; 



(1993) 



