| | The genera of Cactaceae |
The plants succulent; cerioid to condensed-cactoid (soft-fleshy); low and very compacted in their entirety, or not ‘low and very compacted’. The stems spiny; low, slender, shortly cylindric to elongate cylindric. The plants basally branched, or unbranched, or offsetting; prostrate, or erect; solitary, or clustering; to 0.03–0.06 m high. The stems not segmented; prominently low- ribbed and grooved. The ribs 6–12; longitudinal. The plants conspicuously tuberculate. The tubercles connected by the ribs; borne in longitudinal series (along the ribs). The areoles associated with tubercles; borne in longitudinal series (along the ribs); simple; woolly; without bristles; with spines. The spines clustered; 6–19; 0.5–6 cm long; with radials and centrals differentiated (radial spines acicular, the centrals often hooked). Central spines 1–4. Radial spines 6–15. The spines usually usually including some hooked members; straight, or curved, or hooked. The mature stems leafless.
Flowering during the day. The flowers terminal, or lateral; one per areole; shortly tubular, or campanulate, or bowl-shaped; sessile; medium-sized to large; 3.5–6 cm long; regular. The receptacle conspicuously produced beyond the ovary into a tubular hypanthium. The hypanthial tube short, bearing small scales and areoles with wool and hairs or bristly spines; not naked; with scales; with spines, or spineless. The perianth pinkish yellow. The perianth segments relatively short, broad; blunt (or retuse), or apiculate. Stamens adnate to the perianth (inserted in the throat and tube); in groups (in two series, the lower ones forming rings around the styles). The stigma lobes red.
The mature fruit to 5 cm long (in the only species recorded ...); globose, or ellipsoidal; green (-ish); not naked (with wool and bristles); without spines; with persistent floral remains; non-fleshy when mature; dry, irregularly or basally dehiscent. The seeds 2–2.5 mm long; brown to black; broadly oval; not encased in bony arils; with hilum and micropyle conjunct. The testa rugose. Cotyledons reduced or vestigial.
Natural Distribution. Western and southen Argentina, central and southern Chile, Patagonia.
Classification. 5 species. Subfamily Cactoideae. Tribe Notocacteae.
Cf. Hunt, 1967.
Images. • Austrocactus bertinii: Britton & Rose (1922).
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’.
