This forms a simple umbel (UMBELLA simplex); but generally each of these spokes or peduncles is terminated by a number of smaller spokes, forming a little umbel (UMBELLULA) on the point of each. Fig. 63. The primary spokes or rays (a) compose what is called the universal umbel; and the secondary spokes (b, b) of the umbellulæ form the partial umbel. In Fig. 62., therefore, there is only the universal umbel; in Fig. 63. both universal and partial. The green leaves (c, c) at the base of the universal umbel are the INVOLUCRUM, and this, therefore, is named a universal involucrum (INVOLUCRUM universale). But there are also similar leaflets at the base of the partial umbel (d, d), which, of course, form the partial involucrum, or involucellum. CYMA ; the cyme much resembles the umbel in the primary spokes, as they all spring from one point. But the partial peduncles, in place of going off regularly in the same manner as the rays of the umbellulæ, are scattered without order upon the main peduncles; and the flowers form a flat surface on the top. Fig. 64. The Laurustinus (Viburnum Tinus) and the common Elder (Sambucus nigra) afford ready examples. In the umbel, then, a number of peduncles go from one point, and are terminated, each, by a flower forming the simple umbel, or by smaller peduncles from one point also, forming the compound umbel. In the cyme, though the primary rays start from one point, the partial ones do not, but are scattered irregularly, and this, together with the flowers, forming a flattish surface, constitutes the characteristic of the CYME. CORYMBUS, the corymb (xopus (korus), a helmet), is easily understood. In it the peduncles do not go off at one point, but spring from the central peduncle or stem at various heights above each other. The lower ones, however, are proportionally longer than the upper, and the consequence is that the flowers are nearly all upon a level. Fig. 65. When the peduncles of a CORYMB are very crowded, so that the flowers form a dense bundle, as in sweet-william, the term fascicle (fasciculus, a bundle, Lat.) is used. RACEMUS, a raceme; a peduncle, having short lateral branches. It is generally pendulous. Laburnum affords a good example. SPICA, a spike. Like the raceme, it is composed of one general peduncle, supporting the flowers; but it has no pedicels or partial peduncles; or, at least, these are so short as not to attract notice. Wheat, barley, and lavender are familiar examples, In the raceme the flowers are all nearly blown at the same time, but in the spike the flowering commences at the base, and gradually goes on to the top, so that the first-blown flowers are often dead and faded long before the upper ones expand. * Fig. 66. (a) * Smith's Introduction, p. 176. SPIKELET. CAPITULUM. 197 As umbellula means a partial umbel, so SPICULA, a spikelet, means the partial spike which occurs in grasses. Fig. 66. (b) * Fig. 66. a CAPITULUM, a nead (caput, the head, Lat.); when the flowers are sessile, and joined into a round ball, as in globe-flowered Buddlea (Buddlea globosa) or common clover (Trifolium repens). VERTICILLUS, a whorl. (Fig. 67. See page 128.) Fig. 67. * "Spicula est partialis spica." - Phil. Bot. 223. PANICULA, a panicle; a kind of branching or diffused spike, composed of a number of small spikes, which are fixed along a common receptacle or foot-stalk.* Fig. 68. Fig. 68. THYRSUS, a thyrse (Jvw (thuo), to burst forth). According to Linnæus it is a panicle contracted into an ovate form. The common lilac (Syringa vulgaris) and the privet (Ligustrum vulgare) are familiar examples. The term was "put for branches, or the flame of a lamp or torch, which have a conical form. Hence the spear, with ivy bound about the head, carried in sacrifices to Bacchus, was named Thyrsus."+ And lo! the love-alluring fair, Her Thyrsus brandishes in air, With clustering ivy wreathed around, AMENTUM, ament, or catkin; the last "from the French chaton, on account of its resemblance to a cat's tail." "A species of calyx, or rather of inflorescence, from a common chaffy gemmaceous * Barton's Elements of Botany. † Martyn. Fawkes's Anacreon, ode vi. |