descriptions of this species appeared in "ann. nat. hist." ii. (1839) 375;—"proc. linn. soc." i. (1839) 4; "trans. linn. soc." xviii. (1841) 307, t. 22; "dc. prodr." ix. 233; kuntze in "jahrb. bot. gart. berl." iv. (1886) 270; engl. in "engl. jahrb." x. 255; k. schum. in "engl. & prantl, pflanzenf." iv. 3b, 233.