| | The genera of Cactaceae |
~ Espostoa, (Hunt, 1967)
Including Zehntnerella Britton & Rose
The plants large, cerioid; not ‘low and very compacted’. The stems very spiny; elongate cylindric; pseudocephaliate (laterally), or neither cephaliate nor pseudocephaliate. The plants much branched (from near the base, sometimes with as many as 40 branches); erect; shrubby, or tree-like (Facheiroa s. str. to 5 m high, Zehntnerella with branches to 4 m long); usually with well formed trunks (these short), or not developing conspicuous trunks; to 1.5–8 m high. The stems columnar. The branches differing in form from the main stem (with short trunks), or resembling the main stem. The main stem more or less cylindrical. The stems not segmented; ribbed and grooved. The ribs 15–20; longitudinal; low, rather crowded. The grooves fairly deep and narrow. The plants not conspicuously tuberculate. The areoles not tubercle-associated; fairly distant; borne in longitudinal series; small, round, simple. The flowering areoles differing in form from the non-flowering ones (when asociated with lateral cephalia), or resembling the non-flowering ones. The areoles without glochids; with spines. The spines clustered; 10–20; 0.5–4 cm long; with radials and centrals differentiated (the centrals longer). Central spines 1–5. Radial spines 8–15. The spines stiff; straight; terete (acicular); nut-brown. The mature stems leafless.
Flowering at night. The flowers lateral; one per areole; tubular; sessile; medium-sized; 3–4.5 cm long; regular. The receptacle more or less conspicuously produced beyond the ovary into a tubular hypanthium to scarcely produced beyond the ovary. The pericarpel bearing numerous small, imbricate scales with axillary hairs. The hypanthial tube not naked; with scales (these numerous, small, imbricate). The axils of the scales of the hypanthial tube not naked (with hairs). The hypanthial tube spineless. The perianth members short; white, or red to pink, or brown; limb relatively large, or short or none. The perianth segments recurved (at least, in F. squamosa); relatively short, broad; pointed. The androecium including staminodes (in Zehntnerella), or without staminodes. Stamens adnate to the perianth (inserted in the throat); in groups (the lowermost members on a collar partially enclosing the nectar chamber).
The mature fruit to 1.5–6 cm long; globose; translucent, green, or brown, or purple; not naked (with small scales and brownish hairs in Facheiroa s.str.); without spines; with persistent floral remains (Zehntnerella), or without persistent floral remains; indehiscent. The seeds brown to black; obovate, curved; not encased in bony arils; with hilum and micropyle conjunct. The testa very verrucose. Cotyledons reduced or vestigial.
Natural Distribution. Northeastern Brazil.
Classification. 3 species (F. cephaliomelana, F. ulei, Zehntnerella squamosa). Subfamily Cactoideae. Tribe Trichocereeae.
Images. • Facheiroa ulei: © Zoya Akulova (2010).
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’.
