Xerophyte

Seeds

black, shining, 2.5 cm. long.

Note

It (and all the barrel cacti) consists almost entirely of a very wide cortex - the pith is narrow and the wood (vascular bundle) is very thin. Many non-cactus succulents have very broad shoots like this, but those are invariably due to a large amount of parenchymatous wood.

Flowers

Numerous, yellow, 4 to 5 cm. long; scales on the ovary linear, their axils bearing an abundance of wool covering the ovary with a dense felty mass; upper scales narrow, rigid, more or less spiny tipped; outer perianth segments ovate, longapiculate, with ciliate margins; inner segments oblong, obtuse, retuse or apiculate, serrulate.

Spines

Stout, subulate, distinctly banded, especially the stouter ones, at first yellowish but soon reddish brown; radial spines usually 5 or 6, to 4 cm long, central spine solitary, 4 to 5 cm. long, straight.

Ribs

on young plants as few as 8, broad, high, and more or less undulate, but in old plants very numerous and rather thin.

Stem

Simple, large, cylindric, to 2 meters high, 6 to 10 dm in diameter, dull green and, when young, with broad (purple) horizontal bands, very woolly at the crown.

Fruits

Hidden in amass of soft white wool, oblong, 4 to 5 cm long.

Areoles

Remote on young plants, confluent in old flowering plants.