Xerophyte

Habit

The following description of this species is mainly based on old literature, Förster (1847), Britton & Rose (1920) and Werdermann (1939). Pilosocereus glaucescensSN|6800]]SN|6800]] is an erect, branching plant with beautiful frost-blue rounded ribs, somewhat inflated, close-set areoles with numerous whitish bristles and hairs. Few cacti have this wonderful colour. The apex of stems bears short, yellowish spines and pretty closely tight white wool. In their native Brazil, these cacti grow to the size of a small candelabra-like tree up to 6 meters high and as wide and in summer are covered with white flowers developing from a white woolly cephalium at stem tip. Grown indoors in containers, they slowly form upright columns to 1.2-2 metres tall and develop branches, but rarely flower.

Flowers

From a pseudocephalium (clesely set white woolly areoles) that develops on one side of the branches, about 6-7 cm long,. Ovary wide and flat, about 5 mm long and almost 2 cm in diameter, outside nacked and shiny green. Tube about 3.5-4 cm long, cylindrical, slightly enlarged outward above, glaucous olive-green with bracts up to 1.5 cm long, inside whitish. Stamens, fused for about 2 cm to the tube at the base, becoming free only in the upper part. Filaments white. Anthers pale yellow. Innermost stamens, closely set against the style. Style about 4 cm long, white, strongly tapering upwards, with 12 white, stigma-lobes about 3 mm long, slightlyspreading.

Spines

Radiating, of different lengths and thicknesses, biserial, the exterior (radials) 10-13(-18), fine, transparent, yellowish to brownish, straight, divergent, inserted to the number of 5 or 6 (or more) on each side of the areole, about 5-15 mm long, the lower longest. The interior (centrals) 5-7, stouter, disposed irregularly in the centre, clearly distinguishable from the radial spines, dull yellow or grey-yellow, at the base somewhat thickened and brown, about 10 to 15 mm long,

Ribs

8-10 rounded, blunt, inflated, about 1.5 cm high, separated by sharp sinuses, with age becoming effaced toward the base of the stem.

Stem

Erect, 8-10 cm in diameter by about 6 m in height at first simple, later strongly branched, dark bluish grey, glaucescent particularly in the new shoot.

Areoles

Quite large and close together ( about 1 cm apart), almost confluent toward the base of the stem, rounded, with short silver-grey almost black tomentum, furnished with hairs and very abundant, fine, undulating, weak, white bristles about 1 to 2 cm long, especially on the areoles recently developed and toward the summit of the stem, rarer on the lower areoles.