A Grammatical Dictionary of Botanical Latin

Umbo, 'a rounded elevation or protuberance at the end or on the side of a solid organ' (Gleason 1952), such as on the ends of scales of some pine cones; (fungi) with a central prominence on the pileus surface opposite the stipe; (fungi) “(of the pileus) a raised, conical to convex knob or mound on the center; a boss” (S&D); opp. umbilicus, q.v.; umbo,-onis (s.m.III), abl. sg. umbone, nom.& acc.pl. umbones, dat. & abl. pl. umbonibus [> L. Umbo,-onis (s.m.III) 'boss of a shield; a projecting part of a precious stone, a knob, boss, the full part or swelling of a garment;] opp. umbilicus, q.v.; cf. mammilla;

- drupa tenuiter carnosa, ovoidea, calycis limbo parvo coronata, inter lobos umbone parvo terminata (B&H), drupe thinly fleshy, ovoid, crowned with the little limb of the calyx, between the lobes ended by a small umbo.