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| The genera of Cactaceae |
The plants succulent; cerioid; not ‘low and very compacted’. The stems spiny; elongate cylindric. The plants much branched; erect; shrubby to tree-like (usually with more or less erect branches and broad crowns from short trunks); with well formed trunks (these initially short); to 1–5 m high. The stems columnar, or not columnar. The main stem not remaining dominant; more or less cylindrical. The branches cylindrical. The stems not segmented; ribbed and grooved. The ribs 5–8; longitudinal; blunt. The grooves wide. The plants not conspicuously tuberculate. The areoles not tubercle-associated; fairly closely approximating; borne in longitudinal series; simple; with spines. The spines clustered; 6–10; 0.2–7 cm long; with radials and centrals differentiated (the central usually longer). Central spines 1. Radial spines 5–9. The spines straight, or curved. The mature stems leafless.
Flowering during the day, or at night and during the day. The flowers lateral; more than one per areole (up to 9 per areole); rotate; sessile; medium-sized; 2.5–4 cm long; regular. The receptacle scarcely produced beyond the ovary. The pericarpel with small scales having woolly axils but no bistles. The hypanthial tube not naked; basally with scales (these small). The axils of the scales of the hypanthial tube not naked (slightly woolly). The hypanthial tube spineless. The perianth exposed during bud development; rotate; green to white, or cream. Stamens rather few.
The mature fruit 1–2 cm long; globose; naked; without persistent floral remains; sweet tasting, fleshy; berry-like, indehiscent. The seeds truncate at the hilar end, black; pyriform ("obovate"); flattened; not encased in bony arils. The testa dull; verrucose. Cotyledons reduced or vestigial.
Natural Distribution. Mexico, Guatemala.
Classification. About 4 species. Subfamily Cactoideae. Tribe Pachycereeae (?).
Images. • Myrtillocactus cochal: © Zoya Akulova (2017). • Myrtillocactus geometrizans and M. schenkii: Britton & Rose (1920).
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’.
