Description of Turbinicarpus mandragora ssp. booleanus

T. mandragora ssp. booleanus [Click the image for more pictures]

Photo © Mark Faint

George S. Hinton, Phytologia 80(1):62-63, 1996.

Latin: Turbinicarpus mandragora (A. Berger) A.D. Zimmermann et T. subterraneus (Backeberg) A.D. Zimmermann var. subterraneus simile quoad radix tuberascens per collum gracilem ad caule connexa; caulibus singulis partim hypogaeis depressi-obovatis; collo hypogaeo plerumque 2-5 cm longo; in quoque areola spinis centralis duabus, superiore antrorsa inferiore porrecta, ad basim albis cetero atrobrunneis vel nigris; spinis radialis vulgo 18-20 ubique albis vel apicem versus rubris vel brunneis; floribus magenteis; fructibus longitudinaliter dehiscentibus pulverulentis, squamis duabus stramineis Ca. 1 mm longis.

Stems single, rarely branching, broadly obovate, 2.5-4.5 cm high, 2.5-5.5 cm in diameter, basally truncate in older specimens. Roots connected to the stem by a narrow, hypogeous neck; neck 1-5cm long, 3-5 mm in diameter, usually straight but occasionally curved or angled. Roots tuberous, pyriform to globose, 0.8-2.8 cm in diameter, 1.2-5.7 cm long. Stems tuberculate, the axils bare; tubercles rhomboidal in cross section, lacking a dorsal sulcus, green, white-dotted, ca. 4 mm high, ca. 5 mm wide at the base, arranged in 13 and 21 spirals. Areoles elliptical 1.5-2.0 mm long, 1 mm wide, villous near apex, later glabrous, ca. 8 mm apart. Central spines 2, ca. 0.3 mm in diameter at the base, terete, proximally white, turning brown, then black above, the apical antrorse, mostly 12-15 mm long, ranging from 10 to 24 mm, the basal porrect, mostly 12-18 mm long, ranging from 10 to 21 mm. Radial spines mostly 18 to 20, rarely as few as 14 or as many as 28, acicular, white, the extreme apex usually brown or reddish; the lower most (retrorse) radial spines shortest, these ca. 3-6 mm long and 0.1 mm in diameter at the base, progressively longer above, the uppermost (antrorse) radial spines longest, usually ca. 17 mm, rarely to ca. 29 mm long, 0.2 mm in diameter at the base. Flowers ca. 2 cm in diameter, ca. 2.5 cm high. Outer perianth segments oblong, entire, mucronulate, the lower most ca. 8 mm long and 3 mm wide, with a white, translucent margin, mid-vein green, becoming dark purple above. Inner perianth segments narrowly oblanceolate, apex emarginate and often mucronulate, ca. 15 mm long and 4 mm wide, pale to dark magenta with darker mid-vein. Anthers yellow; filaments yellow. Style ca. 11 mm long; stigma lobes 7 to 9, pale yellow, protruding ca. 5 mm above the anthers. Fruit dark green to purple, pulverulent, longitudinally dehiscent, ca. 6 mm in diameter and 7 mm high, attached at the base of an apical areole, with two stramineous scales ca. 1 mm long.

Locality: Nuevo León, México.

Related taxa

Turbinicarpus mandragora ssp. booleanus was originally a member of the genus Rapicactus and is now part of the mandragora aggregate of taxa, together with the following:

References

George S. Hinton, Phytologia 80(1):62-63, 1996.

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