Xerophyte

Description

Backebergia militarisSN|5340]]SN|5340]] (Pachycereus militarisSN|5338]]SN|5338]]) is a tree-like cactus, up to 5-6 m hight, with numerous erect branches that feature a special terminal cap (cephalium; Latin for head) from which the small flowers push out. When the stem is about 6 m tall, each shoot tip is converted into a dense head of helically arranged tubercles, some of which produce flowers, and the crowded areoles and flowers are protected by numerous long, golden bristles. This bristly cephalium grows from the tip, where new areoles and flowers are produced, and the oldest bristles blacken with age.

Flowers

The flowers are nocturnal appear, solitary and casually distributed, on the portion of inflorescence formed in the years preceding the new vegetative phase. The flowers have a shape that specializes them for attracting moths

Ribs

For many years each upright young branch has about 5-7 ribs but does not produce flowers. Later the number of ribs encrises to 9-11.

Stem

Numerous, cylindrical, 5-6 m tall, erect c. 12-15 cm in diameter, dark greyish green. It grows rapidly, over a meter per year, and each new growth is revealed by a constriction. Usually there are no secondary branches; plants grow solitary until they are about three meters high. In adult and old plants the stem is enlarged at the base and forming a showy dark brown foot. The larger and older specimens have many broken branches, and stems break most easily where there are constrictions. B. militaris is one of those species where darkening of an exposed wound occurs.

Fruits

Oblong, 3.5 x 2 cm, red at first, soon dry, bristly at the apex only with has few seeds (10-20). The remains of the dry flower adhere to the fruit and extend outwards from the inflorescence’s bristles.

Areoles

5-10 mm apart.