[f. VERTICILLATE a.: see -ATION.] The formation of verticils; a verticillate form or structure, a verticil.
1830. Lindley, Nat. Syst. Bot., 297. The degree of verticillation requisite to constitute a calyx.
1843. Penny Cycl., XXVI. 131/2. The tail is rounded…; its verticillations are composed, above, of large tubercles, and below, of flat, quadrangular scales.
1888. Riverside Nat. Hist., I. 167. In the Diadematidæ the spines are hollow, long, and set with rings or verticillations.
