. Annual report of the Board of Regents of the Smithsonian Institution . Fig. 3.—Opuntia joint, with leaves. (pi. 10, fig. 2), or cylindrical, or awl-shaped and caducous, as in thegenera Opuntia and Xopalea. In the axils of the leaves are situated the areoles. These are little cush-ions clothed with down or felt-likewool from which the spines issue,and in some genera the flowersalso. In Opuntia and Pereskiopsis,in addition to the spines, theyusually bear a tuft of small, short,barbed bristles, called glochides orglochidia. SPINES. The spines are not connectedwith the woody axis of the stemor b
. Annual report of the Board of Regents of the Smithsonian Institution . Fig. 3.—Opuntia joint, with leaves. (pi. 10, fig. 2), or cylindrical, or awl-shaped and caducous, as in thegenera Opuntia and Xopalea. In the axils of the leaves are situated the areoles. These are little cush-ions clothed with down or felt-likewool from which the spines issue,and in some genera the flowersalso. In Opuntia and Pereskiopsis,in addition to the spines, theyusually bear a tuft of small, short,barbed bristles, called glochides orglochidia. SPINES. The spines are not connectedwith the woody axis of the stemor branches, but emerge from theareoles, as indicated above. Insome species they are simple andstraight, either bristle like, awl-shaped, or short and conical. Inothers they are bent like fishhooksor curved and horn-like, with trans-verse ribs (pi. 13, fig. G). Some-times they are minutely pubescent or hairy and sometimes even plumose or feathery (pi. 3, fig. 6). They may be grouped in star-like clusters, with straight or curved. Fig. 4.—Cactus spines. 540 ANNUAL, REPORT SMITHSONIAN INSTITUTION, 1908.
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