| | The genera of Cactaceae |
The plants succulent; condensed-cactoid; low and very compacted in their entirety. The stems spiny; discoid to globose, or shortly cylindric (sometimes becoming so); not apically depressed; apically woolly. The plants terrestrial and self supporting; unbranched; erect; solitary; to 0.11 m high (and 10 cm in diameter). The stems not segmented; conspicuously ribbed and grooved. The ribs about 18–22; longitudinal. The grooves deep and narrow. The plants not conspicuously tuberculate. The areoles not tubercle-associated; closely approximating; borne in longitudinal series; simple (elliptic, extending along the edges of the ribs); initially woolly (but soon becoming naked); with spines (but these soon shed). The spines clustered; initially 3; 0.5–1.2 cm long; showing little or no difference between radials and centrals; slightly curved; light coloured. The mature stems leafless.
Flowering during the day. The flowers solitary; terminal; one per areole; funnelform; sessile; small to medium-sized; 2–4 cm long; regular. The perianth deep pink, or red (to majenta). The perianth segments relatively short, broad; pointed.
The mature fruit to 9 cm long; naked; without persistent floral remains; hidden in the apical wool, berrylike; dehiscent to indehiscent; if dehiscent, irregularly dehiscent. The seeds 1.2 mm long; black; ovoid; not encased in bony arils. The testa shiny. Cotyledons reduced or vestigial.
Natural Distribution. Mexico.
Classification. 1 species (G. mexicana). Subfamily Cactoideae. Tribe Cacteae.
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’.