Monsonia angustifolia, commonly the crane’s bill and in Afrikaans the angelbossie (little sting bush), is an annual bearing erect or decumbent stems to heights around 30 cm. The reddish purple stems are hairy, the hairs sometimes glandular.
The narrowly oblong to elliptic leaves have slightly and unevenly toothed or scalloped margins. The specific epithet, angustifolium, is derived from the Latin words angustus meaning narrow and folium meaning leaf, referring to the leaf-shape.
The blades fold in along their midribs and a few lateral veins ascend strongly to the margins. Lower leaves are alternate, upper ones opposite. The leaf dimensions are 2,5 cm long and up to 1 cm wide. The leaf petioles may be 1 cm long and the straw-coloured stipules are often spiny.
The flowers grow from leaf axils, mostly solitary, sometimes up to three in one inflorescence. The flowers have slender pedicels and narrow calyx lobes.
The usually solitary flowers have five mauve or pink petals, rarely white while blue and yellow have been mentioned. Each petal bears five grey or dark blue veins from base to near the truncated tip. Flowering happens from late spring to early autumn.
The erect fruits of 5 cm long have beaked tips comprising the style remains that become twisted as they dry.
The species distribution is widespread in the east of South Africa from the Eastern Cape through KwaZulu-Natal and the Free State to the provinces north of the Vaal River and further in tropical Africa.
The habitat is bushveld and grassland in the summer rain region, the plants often found in disturbed places. The species is not considered to be threatened in its habitat early in the twenty first century (Pooley, 1998; Van Wyk and Malan, 1997; Germishuizen and Fabian, 1982; iNaturalist; http://redlist.sanbi.org).