Leucospermum calligerum is a softly hairy shrub, with wand-like branches, entire ovate leaves that have a bony tip of about 25 × 6 mm (1 × ¼ in), and globular heads of 2–3½ cm (0.8–1.4 in) in diameter, with two to six together near the tip of the branches and flowering in turn, that consist of 4-merous flowers, initially cream-colored, later pink, with the petals curled and the styles 2–2½ cm (0.8–1.0 in) long, sticking out like pins from a cushion. It is called arid pincushion or common louse pincushion in English and rooiluisie in Afrikaans. Well-scented flowers can be found from July to January. It naturally occurs in fynbos in the Northern Cape and Western Cape provinces of South Africa.
Description
Leucospermum calligerum is a shrub of ½–2 m (1½–6 ft) high and up to in circumference, with a single main stem at its foot, wand-shaped stems, branching at wide angles, initially horizontal or directly rising up, generally long, thick when flowering, covered in minute soft crinkly hairs and also with longer soft straight or curvy hairs. Its simple, tough, leathery, grey to olive-colored, oval to long-oval leaves are set alternately, overlapping or more scattered along the branches, and have a blunt or pointy thickened tip, sometimes with two or three very small teeth, with a rounded or narrowing base, long, and 4¼–8½ mm (0.17–0.33 in) wide, often with distinct veins, greyish due to minute soft crinkly hairs and sometimes with longer soft straight or bend hairs, often felty when young.
The hemisphere-shaped flower heads are nearly seated or sit on a stalk of up to long, mostly with two to six together, rarely individually, near the end of the branches. Older clusters of flower heads can be overtopped by young growth and then appear to be placed along a branch. Each flower head of 2–3½ cm (0.8–1.4 in) in diameter, is subtended by an initially cup-shaped involucre of narrow, strongly overlapping, woolly, rubbery (or cartilaginous) bracts of with a pointy tip with tufts of long, fine hairs. The individual flower bud is a straight, pale green, 1½–1¾ cm (0.60–0.67 in) long tube, brown opposite the anthers, set with long straight silky hairs. When the flower opens, a tube of ½ cm (0.2 in) long remains, while the four lobes curl back when the flower opens, which are initially cream and later get flushed pink. The style is 21–25 mm (0.83-0.98 in) long, is narrower towards the tip and slightly bend towards the center of the flower head, pale at the base and carmine pink towards the tip. The pollen-presenter, a thickening at the tip of the style (comparable with the "head" of the pin), is conical to oval in shape and yellow in colour, about 1 mm (0.04 in) long, initially carrying bright yellow pollen. The stigma is a transverse groove at the very tip of the pollen-presenter. At the base of the ovary are four awl-shaped, so-called hypogynous scales of about 2 mm (0.08 in) long. The fruit is oval, blunt, almost hairless, and ¾ cm (0.3 in) high. The flowers of Leucospermum calligerum are sweetly scented.
The subtribe Proteinae, to which the genus Leucospermum has been assigned, consistently has a basic chromosome number of twelve (2n=24).
Differences with related species
L. calligerum looks very much like L. wittebergense, known from the Swartberg range and other peaks surrounding the Little Karoo, north-east of the distribution of L. calligerum. L. wittebergense has a style of 12–19 mm (0.47-0.75 in) long and a spindle-shaped pollen-presenter, while L. calligerum has a 21–25 mm (0.83-0.98 in) long style and an ovoid to conical pollen-presenter.