Echinocactus rhodophthalmus Hooker, Bot. Mag. 76: pl. 4486 (1850).
ECHINOCACTUS rhodophthalmus; solitarius subelatus conico-columnaris profunde 8-9 sulcatus, costis obtusis crenato-tuberculatis tuberculis compressis sub-hemisphæricis, areolis obsolete lanatis, aculeis subnovem validis rectis purpureo-fuscis demum pallidis, centrali subduplo majore, calycis tubo obconico squamoso inermi squamis sepalisve ovatis albomarginatis, petalis spathulatis roseis basi intense rubris.
Received from Mr. Staines, who procured it from the neighbourhood of San Luis Potosi, Mexico, and we do not find the description of any species to correspond with it. In its flourishing state it is exceedingly handsome, the deep red of the base of the petals forming a ring, as it were, round the densely-clustered stamens and bright yellow rays of the stigma, adding much to the beauty of the blossom. It flowers with us in August.
DESCR. Our plants are from four to five inches high, sub-columnar, but tapering upwards almost from the base, deeply cut into about eight or nine furrows, the ridges obtuse, but formed into lobes or tubercles by transverse lines; the tubercles are sub-hemisphærical but compressed; the areolæ furnished with obscure wool: the spines about nine, strong, straight, tapering, flattened, at first deep purple, afterwards pale and almost colourless, length from three-quarters of an inch to an inch, mostly spreading, but the central one, which is much the longest and strongest, stands forward. The flowers are produced from the summit of the plant, large, handsome. The calyx-tube (or green portion) about an inch long, obconical, quite destitute of spines or setæ, but with the scales or sepals ovate, brown with pale margins, gradually passing into the long, linear-spathulate, acute, spreading, bright rose-coloured petals, which have a dark red almost crimson spot at the base, forming a radiating circle around the column of stamens and style. Stamens numerous, very compact: filaments white slender: style as long as the stamens: stigma of nine or ten spreading, bright yellow rays, covering the anters.