Astrophytum caput-medusae

Name and identification

The correct botanical name is Astrophytum caput-medusae (Velazco & Nevárez) D.R.Hunt. The species was described in 2002 as Digitostigma caput-medusae and transferred to Astrophytum in 2003. It resembles a clump of long fingers emerging near ground level. These elongated parts are stem tubercles. [2-WWW] [Montanucci 2009]

Stem, roots and areoles

The main stem axis is very short. The plant produces a fleshy, spindle-shaped storage root and thinner lateral roots. Tubercles are slender, covered in small pale hairs. Spine-bearing areoles occur at their tips, with larger flower-bearing areoles slightly lower on the side facing the plant axis. This separation of areole functions is a distinguishing feature. [Montanucci 2009]

The Cactus Art description gives tubercles up to 190 mm long and 2–5 mm wide. Spines are few, zero to four, and 1–3 mm long. These values describe the species, rather than dimensions required for first flowering. Old tubercles can die as the plant produces new ones. Loss of a single tubercle and progressive breakdown of the plant base require different assessments. [11-WWW]

Flowers, fruits and seeds

Yellow flowers with orange colouring at the bases of the inner tepals arise on developing tubercles. Young fruit is green and fleshy. As it ripens it may turn pink, dries and splits irregularly lengthwise. Seeds are dark, with a distinctly sculptured surface and a deep depression near the base. These features combined with DNA analysis support inclusion in Astrophytum. [Vázquez-Lobo et al. 2015] [Montanucci 2009]

Range and habitat

The current POWO record lists Nuevo León and Tamaulipas. The older Cactus Art page lists only Nuevo León. This narrower entry reflects the scope of the older account. Plants are associated with northeastern Mexican scrub. Partial shrub shade matters practically when interpreting the species' light needs. [2-WWW] [11-WWW]

Cultivation in Poland

A reasonable starting point is a very bright site with diffuse light and a container accommodating the root without bending it or leaving a large excess of wet substrate. During repotting, examine the boundary between short stem and root. Pot selection follows plant structure, rather than tubercle length alone. This is a practical inference from the morphological description. [Montanucci 2009] [11-WWW]

Early Cactus Art observations involved few plants. The authors noted differences between grafted specimens and plants on their own roots. In grafted plants, drought could rapidly kill tubercles. This supports observing the particular plant and rootstock. It does not establish a universal watering rhythm. [11-WWW]

The collected materials do not define a proven numerical overwintering protocol in Poland for this species. Young plants, grafted specimens and adults on their own roots need separate management. Temperature and watering should account for root activity and tubercle responses. Individual reports of cold survival do not translate into guaranteed frost hardiness. [11-WWW]

Propagation and documentation

The species is propagated from seeds and also occurs grafted in collections. The materials mention in vitro culture trials. Their description does not provide a full comparative protocol for this species. The author's general articles on media, equipment and establishing cultures provide methodological background. They are not an experiment on A. caput-medusae. [11-WWW] [Anonim b.d.m] [Anonim b.d.n] [Anonim b.d.l]