cactus, with strong underground tap-roots and deciduous
Stem: The thin cylindrical segment usually arises basally from
the root-stock (or rarely joined).
Stems are green to brown, 3-10 cm long
and 0,5-1 cm in diameter.
napiform, cream-coloured, up to 15 (or more) cm long.
Very woolly, without (or with very few) glochids.
4-5, brown (more or less light)
Radial spines: 10-20: very small, glassy, placed almost
horizontally against the stem's
surface, up to2 mm long.
rotate, yellow to dirty-yellow, up to 3 cm in diameter, growing apically at the tip of new stems without a clear floral tube
Blooming season: Summer.
Dry and larger than the stem itself, dehiscing
transversally in the upper part,
opening up like a cap and setting the seed free.
Seed: Typical of the genus, winged,
with a strongly flattened
aril; uneven on its periphery.
wild during severe
shoots die back to the
rains return, the rootstock produces new green shoots that grow
upward until they reach the
soil surface. Similarly in cultivation -
when top growth is
pruned, the plants produce new green
stems bearing terminal
flowers that open in the late
spring or early
case old Pterocactus
branches easily detach spontaneously at the smallest collision.
They are nearly
deciduous!!! Sometimes a very fragile
necrotic brown zone forms at the branches'
base, helping the shoots to break up at the point of union of
This helps the plant to
naturally produce new
Cultivation: Pterocacti are easy to grow, provided they are kept
cold, but dry during autumn and winter. It is essential to give
full sun; otherwise they will become atypical. If grown in full sun, the
new growth will bloom profusely in spring and summer.
Most of the slender stems become detached during winter, but some
advise (to help plant) pruning all the top growth in autumn,
in order to encourage
it to produce stems with terminal flowers in the spring.