together.  The plant is a native of California, and was introduced about 1840.  Under cultivation this species proves to be a shy-flowering Cactus, although in a warm house it grows freely, and remains in good health.  It is well adapted for grafting on to the stem of some kind of Cereus, and in this way may be made to look very singular, as was shown in Mr. Peacock’s collection of succulents some years ago, when a fine specimen, over 1 ft. across, was successfully grafted on to three stems of C. tortuosus, and had much the appearance of a melon elevated on a short tripod.

[Illustration:  Fig. 43.—­Echinocactus pottsii.]

E. rhodophthalmus (red-eyed); Bot.  Mag. 4486, 4634.—­Stem cone-shaped, 4 in. to 1 ft. high, deeply furrowed; ridges about nine, 1 in. high, the angles bearing closely-set clusters of radiating spines, with a projecting one in the middle of each cluster, which contains nine spines 1 in. long, purple when young, becoming white when old.  The flowers are produced from the summit of the stem, and have a thick, green, scaly calyx tube, upon which the spreading, rose-coloured petals are arranged in a regular series, and form a shallow bell nearly 3 in. across.  The throat of the flower is coloured a deep crimson, against which the little sheaf of white stamens and the star-shaped yellow stigma form a pretty contrast.  Three or more flowers are expanded together on a plant.  It is a native of Mexico; introduced in 1845.  It thrives in a house or frame where it is protected from frost, and during summer gets plenty of sunlight and air.  It flowers in August.  During the months of April and May, when it starts into growth, it should be kept close; but by the end of June, it should be exposed to the open air and allowed to ripen, so that its flowers may be produced in the autumn.  The plant called E. v. ellipticus does not differ from the type, owing its name to the form of the stem of the first plant that flowered at Kew.

E. scopa. (brush-like); Fig. 44.—­The stem of this species, when seen covered with numerous tufts of bristly spines, has been compared to a brush, a comparison not, however, applicable to the form represented in the Figure.  In height the stems sometimes reach l1/2 ft., with from thirty to forty ribs, bearing little discs of white wool at the bases of the clusters of spines.  The flowers spring from the upper part of the stem (the nodules shown in the illustration represent the places where flowers have been developed at an earlier stage of growth), from four to six being borne in the same season; they are 11/2 in. long and wide, the tube short and brown, bristly; the petals are arranged in several overlapping series, rather wide for their length, toothed at the ends; their colour is a bright sulphur-yellow, as also are the stamens, whilst the stigma, which is rayed, is bright crimson.  Native of Brazil.  Introduced about 1840; it is more like a Cereus, in the form of its stem, than an Echinocactus.  It flowers in June, and requires stove treatment.  The stems, when dried carefully and stuffed with wadding, form pretty ornaments.