The bright red or scarlet flowers of Cyrtanthus angustifolius grow stalked in groups of four to ten at the tips of hollow scapes of about 45 cm tall.
The long, tubular to narrowly funnel-shaped perianths are slightly curved, a feature of Cyrtanthus. The tubes end in six bluntly pointed, somewhat flaring tepal tips, positioned in two whorls of three.
The six stamens grow in two series, sometimes slightly exserted. The style ending in three short branches is exserted in older flowers, further than the anthers.
Flowering begins before midspring, lasting through summer. Pollination is done by sunbirds and certain butterflies.
The seeds are black and flat (Curtis-Scott, et al, 2020; Vlok and Schutte-Vlok, 2015; Manning, 2007; iNaturalist).