Xerophyte

Central Spines

3 or 4, spreading, often forming a cross, lower one often larger than the others, somewhat curved 3-10 cm long.

Seeds

Each fruit contains numerous black seeds approximately 1.3 mm long and 0.9 mm wide.

Description

Echinocactus platyacanthus is a slowly growing barrel cactus known under popular name visnaga, it is usually solitary and grows huge in habitat. It could live more than a hundred years and is easily recognized because of its massive size, by far the largest of all barrel cacti. The stem is grey-blue somewhat tuberculate and nice when small, whilst large plants are heavily ribbed with numerous areoles forming a continuous line. They are day-flowering plants with vivid yellow flowers produced in spring and summer-autumn.

Note

E. platyacanthus (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

The flowers appear from the end of spring to summer and also in autumn, only on larger mature specimens receiving enough full sun, but rarely flowering in cultivation. They are numerous, diurnal, self-compatible, about 2 cm in height and opening fairly wide, 3-6 cm long, 3-8 cm wide, long-woolly, vivid yellow. Mature specimens often have a somewhat sway-backed, saddle-shaped apex, densely covered in white wool, where their flowers emerge. Outer perianth-segments lanceolate, mucronate; inner perianth-segments broad, obtuse, yellow, the outer ones tappering to narrow brownish points. Stigma-lobes 10 open, spreading. Plants that flower in the spring and autumn, produce fruits in summer and winter respectively.

Spines

Variable with age, large, stiff, somewhat flattened, with transverse striations, brownish, yellowish to reddish, at first, greyish or blackish in age

Ribs

Ribs extremely variable in number, 5-20 in young plants, later increasing to 30-60 or more, acute, vertically oriented, more or less tuberculate and nice when small, later hight and even-edged.

Stem

Nearly globular, broadly columnar, or barrel shaped, often very massive 0.5-2.5(-3) metres high, 40-80(-100 or more) cm broad, but much smaller in cultivation, light green to yellowish green, sometimes glaucous, very woolly at apex. Sometimes purple banded when juvenile.

Radial Spines

(3-)4-8(-10), spreading, 1.2-4 cm long often in an upper and lower series.

Fruits

Dry at maturity, oblong to narrowly club-shaped, yellowish, 3-8 cm long, c. 2.5 cm wide, with numerous thin, dry, membranous scales, wool, and hairs; perianth parts persistent.

Areoles

Round, but becoming elliptical to linear and continuous in mature plants.