XANTHORRHOEA (from xanthos, yellow, and rheo, to flow; referring to the resinous juice extracted from the plants). Black Boy; Grass Gum-tree; Grass-tree. ORD. Juncaceae. A genus embracing eleven species of greenhouse, long-lived perennials, with a thick, woody caudex, all natives of Australia. Perianth persistent, of six distinct segments; stamens six; scape or peduncle terminal, hard, often several feet long, terminating in a dense, cylindrical spike of numerous sub-sessile flowers, closely packed with numerous bracteoles surrounding each flower within a small or subulate, subtending bract. Leaves in a dense tuft at the top of the caudex, long-linear, brittle, spreading or recurved, their broader, closely imbricated bases remaining long persistent. Caudex of several species emitting a copious, dark or yellow, resinous gum (the former kind called Black-boy Gum, and the latter Botany Bay or Acaroid Resin). Some of these plants form conspicuous features in Australian landscapes. Those best known to cultivation are here described; all have white flowers, appearing in spring. They thrive in a compost of peat and loam and may be increased by offsets. XANTHORRHOEA arborea (tree-like). Botany Bay Gum. fl., perianth segments about 1/4in. long, three-nerved; spike 3ft. to 4ft. long, 1in. to 1 1/2in. in diameter; scape 5ft. to 6ft. long April. l. flat or triquetrous, 3ft. to 4ft. long, two or three lines broad. Caudex attaining several feet in height, with a diameter of 6in. to 9in. XANTHORRHOEA australis (Southern). fl., spike, when full grown, upwards of 2ft. long, nearly 1 1/2in. in diameter; scape usually about 2ft. high. Summer. l. about 2ft. long, one line or rather more broad, somewhat flat, but with the dorsal angle, and sometimes also the facial one. prominent. Caudex elongated, but rarely exceeding 2ft. in height. 1824. XANTHORRHOEA bracteata (conspicuous-bracted). fl., spike usually 4in. to 6in. long, 1/2in. or sometimes 3/4in. in diameter; subtending bracts subulate and very conspicuous in the young spike; scape 2ft. to 3ft. high. Summer. l. about 2ft. long, one line or rather more broad, concave above, the dorsal angle slightly projecting in the lower part, tapering upwards into a narrow, triquetrous point. Caudex very short. 1810. XANTHORRHOEA hastilis (spear-like). fl., spike 1 1/2ft. to 2ft. long, a dense, rusty tomentum covering the ends of the bracts and outer perianth segments; scape often 6ft. to 8ft. long below the spike. l. 3ft. to 4ft. long, two to three lines broad, flat in front, but with the dorsal angle more or less prominent. Caudex very short, or often scarcely prominent. 1803. (B. M. 4722; F. d. S. 868.) XANTHORRHOEA Minor (lesser). fl., spike 3in. to 6in., rarely 7in. or even 8in., long, seven to eight lines in diameter when fully out; scape, when full grown, often longer than the leaves. l. crowded on the caudex, 1ft. to 2ft. long, one to nearly two lines broad, flat but thick, or more or less triquetrous. Caudex short and thick. 1804. (B. M. 6297.) XANTHORRHOEA Preissii (Preiss').* fl., perianth segments about 1/4in. long, the outer ones oblong, the inner ones broader; spike 1in. in diameter; scape 2ft. to 6ft. long(including the spike, which occupies half to nearly the whole length). April. l. from a short, flat base, 2ft. to 4ft. long, one to two lines broad, rigid, very brittle when young. Caudex thick and simple, short, or attaining 5ft. to 6ft. (sometimes, according to Oldfield, as much as 15ft.). (B. M. 6933.) XANTHORRHOEA quadrangulata (quadrangular). fl., spike 3ft. to 4ft. long, 1 1/2in. in diameter when in flower; scape as long, or longer. l. slender but rigid, 1 1/2ft. long, strictly quadrangular, though sometimes slightly flattened, rarely above one line broad. Caudex lengthening out to several feet. 1874. (B. M. 6075.)