Xerophyte

Habit

It is a spineless columnar succulent plant, usually solitary. A transverse section of the stem reveal a perfect star shaped form (like the common star-fish) giving the plant the appearance of a bishop's mitre (hence the common name Bishop's cap)

Seeds

Dark brown, helmet-shaped, shining, with a large depressed hilum, the margins being turned in.

Description

Astrophytum myriostigmaSN|1845]]SN|1845]] var. tulense , is a naturally occurring form of Astrophytum myriostigmaSN|1845]]SN|1845]] distinguished by very columnar stems up to 90 cm tall. This plant has 5 twisted ribs and is covered with denser white flock, however the number of ribs is not a stable feature; plants typically add additional ribs as the plant matures, increasing to as many as 10. The tulense variety also has smaller yellow flowers. This taxon is self-sterile. It produces viable seeds only with extra pollination.

Roots

Fine, fibrous.

Flowers

Funnelform, usually less than 5 in diameter cm long glossy yellow and sweet scented from the areole at the tip of the stem on mature plant. Outer perianth segments narrow, with brown scarious tips. Inner perianth segments numerous, oblong yellow with a silky shine. Scales on ovary tube scaroious, imbricated, very narrow often bristly tipped, with long wool in their axil.

Blooming Season

Flowers appear intermittently throughout the warm months from April to September. Plants may take up to six years to flower.

Spines

Wanting.

Ribs

Usually 5 increasing to as many as 10 as the plant matures, vertical or twisted, regular, deep, prominent, very broad and sharp to rounded .

Stem

Globular to cylindric up to 90 cm tall (but occasionally up 150 cm tall) and 10-20 cm in diameter, bright green, covered with many minute white hairy scales that give it a characteristic chalk-white or silvery-grey appearance. The scales are composed of very fine interwoven hairs, which, under a microscope, are very pretty object.

Fruits

2-2,5 cm in diameter, greenish to tannish-red, covered with brown, overlapping scales, with long wool in their axil.

Areoles

Closed together