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| The genera of Cactaceae |
Pingpog ball cactus.
The plants condensed-cactoid; low and very compacted in their entirety. The plants’ appearance dominated by crowded interlacing areolar structures obscuring any tubercles, ribs or furrows. The stems spiny; globose; apically depressed. The plants unbranched, or offsetting; erect; to 0.1–0.6 m high (1–6 cm in diameter). The stems not segmented; seemingly not ribbed and grooved (?). The plants conspicuously tuberculate (under the spines). The tubercles 1–3 mm long. The tubercles not connected by ribs; spirally disposed. The areoles associated with tubercles; closely approximating; spirally disposed; small, simple (borne at the tips of the tubercles); without glochids; with spines. The spines clustered; 19–38; 0.1–0.5 cm long; flattened against the stem surface, in several series, but showing little or no difference between radials and centrals; white to pale yellow. The mature stems leafless.
The flowers aggregated; terminal; one per areole (but borne on young tubercles around the apex); campanulate; sessile (?); small (3–12 mm in diameter); 1–1.2 cm long; regular. The receptacle conspicuously produced beyond the ovary into a tubular hypanthium; naked. The hypanthial tube naked. The perianth white, or pink. The perianth segments relatively short, broad. Stamens rather few; adnate to the perianth (inserted in the tube and throat); not exserted.
The mature fruit 0.3–1.8 cm long; clavate; red; naked; non-fleshy when mature; indehiscent (with few seeds). The seeds 1–1.5 mm long; black; ovoid ("oval"); not encased in bony arils. The testa shiny; papillate, or reticulately or striately patterned. Cotyledons reduced or vestigial.
Natural Distribution. Eastern Arizona, west Texas and Mexico.
Classification. 2 species. Subfamily Cactoideae. Tribe Cacteae.
Cf. Hunt, 1967.
Images. • Epithelantha micromeris: Britton & Rose (1922). • Epithelantha micromeris subsp. unguispina: © Zoya Akulova (2015).
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2018 onwards. The genera of Cactaceae: descriptions, illustrations, identification, and information retrieval. Version: 14th November 2021. delta-intkey.com’.
