Astrophytum asterias

Flowering Astrophytum asterias. Areoles and clusters of pale hairs are visible on the ribs.
Flowering Astrophytum asterias. Areoles and clusters of pale hairs are visible on the ribs. Photo Konrad Szychowski.

Name and identification

Astrophytum asterias (Zucc.) Lem. is accepted in POWO. Zuccarini published Echinocactus asterias in 1845, and Lemaire the combination in Astrophytum in 1868. An adult plant has a broad, flattened stem and large woolly areoles arranged in regular rows. Eight flat ribs are usual. The absence of spines and low body profile distinguish it from A. capricorne. [2-WWW] [Anonim b.d.e]

Stem, roots and changes with age

In the archived description, the body reaches about 10 cm in diameter. Plants remain low, and groove depth and rib visibility also depend on hydration. The surface is green to grey-green, with small white hair clusters. The large regular areoles should be distinguished from these much smaller epidermal dots. Both elements can vary greatly in horticultural forms. [Anonim b.d.e] [Lux and Kopunec 1992] [11-WWW]

A grafted plant can have a more elevated growth form than a plant on its own roots. Body size in the description concerns particular material, rather than a limit attainable by every horticultural line. Root condition is assessed through growth and response to watering. Persistent moisture in cool substrate is a common problem described in cultivation materials. [Szychowski b.d.c] [Anonim b.d.e] [11-WWW]

Flowers, fruits and seeds

Flowers open during the day and are yellow with an orange or red centre. The archived profile gives about 4 cm in length and diameter, but size depends on the plant. Seeds are the main means of propagation. Parent plant records and pollination control are needed to preserve batch provenance. Red-flowering forms' flowers should be described in a separate horticultural profile. [Szychowski b.d.a] [Anonim b.d.e] [11-WWW]

Ripe fruit may turn pink and disintegrate, releasing glossy brown seeds. Montanucci places this fruit type in the group associated with opening or breakdown of the basal part. The older archived statement about star-shaped opening at the top has therefore been corrected. The 2003 recovery plan describes ripe fruits gradually disintegrating on the plant. [Montanucci 2009] [U.S. Fish and Wildlife Service 2003]

Range and habitat

POWO lists southern Texas and the Mexican states of Nuevo León and Tamaulipas. Compared with the other species in the 2016 paper, A. asterias occupied lower, warmer sites on average. Mean record elevation was 556.5 m above sea level, with a standard error of 98.1 m. This value describes the set of sites, not a typical elevation for every location or the species' full elevation range. [2-WWW] [Carrillo-Angeles et al. 2016]

Plants can benefit from partial shelter by surrounding vegetation and stones. The low stem is easily overlooked during drought. Conservation studies of the genus highlighted habitat destruction and collection of wild specimens. [Carrillo-Angeles et al. 2016]

Cultivation in Poland

The location should be very bright, with airflow and gradual acclimation to stronger sun. Shelter from prolonged rainfall allows control of substrate drying. Water during active growth after the mixture has dried. The pot should match root size, and the mixture should remain permeable after repeated watering. [Szychowski b.d.c] [Anonim b.d.e]

The archived profile gives overwintering at 7°C, and the genus account 6–10°C for dry, mature plants. These are cultivation experiences and recommendations, without studies defining injury thresholds. In a less stable overwintering space, use a higher temperature and monitor its actual course beside the pots. Seedlings and grafted plants require separate assessment. [Szychowski b.d.c] [Anonim b.d.e]

Sowing requires fresh, labelled seeds, clean substrate and diffuse light. The older profile gives about 25°C for germination, without seed numbers or success data. It can serve as a starting point for observation. Plants with abnormal growth, damaged roots or a valuable phenotype are sometimes grafted. Grafting does not replace provenance records. [Szychowski b.d.c] [Anonim b.d.e]

Forms and similar plants

The names Superkabuto, Ooibo Kabuto, Ruri Kabuto, Hanazono, Kikko, Fukuryu, Hakuun and Akabana are associated with cultivated A. asterias. Additional terms describe rib number, areole arrangement, hair patterns and crested growth, among other features. For a particular cultivated specimen, pedigree may matter more than the trade name alone. [11-WWW] [11-WWW] [11-WWW] [11-WWW] [11-WWW]