A Grammatical Dictionary of Botanical Latin

Thyrsus,-i (s.m.II), abl.sg. thyrso, nom. pl. thyrsi, acc. pl. thyrsos, dat. & abl. pl. thyrsis: thyrse,”a panicle, whose principal diameter is in the middle between the base and apex” (Lindley); a compact panicle, somewhat ovoid, ellipsoid or cylindric in shape, with a main axis that is indeterminate and cymose branches (subaxes): thyrsus,-i (s.m.II), abl.sg. thyrso, nom. pl. thyrsi, acc. pl. thyrsos, dat. & abl. pl. thyrsis [> L. thyrsus,-i (s.m.II), “the main stem of a plant (including the crown and any sideshoots;’ a wand tipped with a fir-cone, tuft of ivy or vine-leaves (orig. concealing a spearpoint) carried by worshippers in the rites of Bacchus” (Glare; Liddell & Scott); > Gk. thyrsos]; in Latin caulis,-is (s.m.III); see stem;

- floribus in thyrsum dispositis, with the flowers arranged into a thyrse (acc.sg.).

- flores solitarii v. varie cymosi, saepe spicas unilaterales thyrsum paniculamve terminalem formantes (B&H), flowers solitary or variously cymose, often forming unilateral spikes or a terminal thyrse or panicle.

- flores parvi, cymulis laxis in thyrsam v. in paniculam late effusam dispositis (B&H), flowers small, with the cymules lax, arranged into a thyrse or in a broadly spreading panicle.

Leptothyrsa Hook. f.; Thyrsodium Benth. & Hook.

NOTE: a loosely spreading panicle would be panicula,-ae (s.f.I) effusa (part.A).

“The Thyrsus, or Thyrse, is a mode of inflorescence very -nearly allied to the panicle, being, in fact, a panicle contracted into an ovate, or egg-shaped form. In the thyrse, the middle foot stalks, which are longer, extend horizontally, whilst the upper and lower ones are shorter, and rise up vertically. We have instances of this beautiful species of inflorescence in Lilac (Syringa vulgaris), in Butter bur (Tussilago Petasites), and other plants.” (Barton).