Solanum guamense, in the Solanaceae (nightshade) family, is medium-sized (2 m, 6.6 ft) shrub with stellate hairs covering the stems, 3 to 4 mm (0.1 to 0.2 in) thick, white flowers, small red tomato-like fruit (5 to 7 mm, [0.2 to 0.3 in]) wide, and thorns on the undersides of the papery, ovate to elliptic-oblong leaves (150 mm x 110 mm, [5.9 x 4.3 in]). Flowers are borne on a hairy forking inflorescence that can be with or without spura (nectar receptacle). The corolla is white with ovate lobes (12 mm, 0.5 in) broad with yellow, blunt anthers. The seeds are flat (2 mm, 0.08 in) long and subreniform (nearly kidney-shaped) to elliptic.