Uncarina grandidieri is a multibranched shrub or small pachycaulescent tree that may ultimately attain a height of 3-5 meters and 80 cm girth. The flower resembles a large Petunia in form and is bright yellow with a dark throat, as in the "Black Eyed Susan Vine" (Thunbergia alata) and give way to green fruit covered in otherworldly spines. The stems are stout and become thickened with age. The leaves resemble those of the cotton plant (genus Gossypium) and are fuzzy and are sticky to the touch, yielding a musty odour when rubbed. The leaves are deciduous during the winter resting season.Derivation of specific name: The species is named in honour of Alfred Grandidier (1836-1921), an intrepid explorer and collector in Madagascar.