Neotropical Basellaceae

Roger Eriksson

University of Gothenburg, Gothenburg, Sweden. 

Description

Perennial, ± fleshy to succulent, herbaceous or occasionally suffruticose vines, or sometimes ± erect plants. Roots fibrous to (at least sometimes) thickened. Stem usually glabrous, rarely asperous or when young puberulent, up to several metres long, sometimes producing subterranean or aerial tubers. Leaves alternate, simple, without stipules, petiolate; leaf blades entire, rarely dentate by glands. Inflorescences axillary or terminal spikes, racemes, panicles, or dichasia. Bracts thin, deciduous or persistent. Pedicels absent or present. Bracteoles 2, opposite, at apex of pedicel or displaced due to elongation of pedicel, deciduous or persistent, usually thin, rarely lacking. Flowers sessile to pedicellate, except calyx actinomorphic, bisexual or rarely functionally unisexual, chasmogamous or cleistogamous. Sepals 2, valvate, opposite, alternating with bracteoles, petaloid, patent to erect, persistent and often somewhat accrescent in fruit, free from each other or partly connate, fused at least at base with petals, usually entire, occasionally with a gibba at base or a dorsal wing (in fruit), at anthesis greenish, whitish, yellowish, or reddish, in fruit pale, brownish, or ± black, membranous to rather thick, rarely fleshy. Petals 5, imbricate, patent to erect, persistent and often somewhat accrescent in fruit, connate only at base or up to c. 2/3 of their length, usually entire, at anthesis greenish, whitish, yellowish, or reddish, in fruit pale, brownish, or ± black, membranous to rather thick, rarely fleshy. Stamens 5, epipetalous, connate and fused only at base or up to c. 3/4 of their length with petals; anthers dorsifixed or basifixed, tetrasporangiate, dithecal, extrorsely dehiscent by longitudinal slits or by short, apical slits; pollen spheroidal to cuboidal, perforate or rarely reticulate, spinulose or not, colpate or porate. Pistil 1, 3-carpellate; ovary superior, syncarpous, unilocular with basal placentation; ovule 1, bitegmic, amphitropous to campylotropous; style 1, undivided to 3-parted almost to the base, or styles 3; stigmas linear to capitate or 3-lobed, rarely bifid or undifferentiated. Fruit indehiscent, nut-like, usually smooth, rarely rugose, in cross section rounded to somewhat hexagonal, surrounded at base to completely enclosed by persistent perianth; embryo annular to cochleate.

Distribution in the Neotropics

  • Anredera Juss.: Mexico to SE Brazil and Venezuela, and the Caribbean Islands.
  • Basella L.: Central America to S Peru and E Brazil, and the Caribbean Islands (introduced).
  • Tournonia Moq.: W Colombia to N Ecuador.
  • Ullucus Caldas: Venezuela to N Argentina.

Distinguishing characters (always present)

  • Small flowers with 2 petaloid sepals and 5 petals, subtended by 2 opposite bracteoles.

Other important characters

Number of genera

4 genera:

  • Anredera (12 spp.).
  • Basella (1 introduced sp.).
  • Tournonia (1 sp.).
  • Ullucus (1 sp.).

Useful tips for generic identification

Key to genera of Neotropical Basellaceae

1. Leaf margin dentate by glands; inflorescence a dichasium...Tournonia
1. Leaf margin entire; inflorescence a raceme, spike, or panicle...2

2. Petals caudate at apex; anthers basifixed, dehiscent by short apical slits …Ullucus
2. Petals obtuse at apex; anthers dorsifixed, dehischent by longitudinal slits …3

3. Inflorescence axis fleshy; flowers sessile...Basella
3. Inflorescence axis not fleshy; flowers pedicellate …Anredera

Status

  • All species of Anredera, Tournonia, and Ullucus are native, and all except a few widespread Anredera species are endemic; the Basella species found in the Neotropics is cultivated and naturalised.

General notes

  • Most species are found in open, dry habitats. Ullucus tuberosus Caldas is an important high Andean food crop, and Basella alba L. is cultivated for its edible leaves. A few Anredera species are grown as ornamentals, also outside their native distributions.
  • The homologies of the (1) bracteoles, (2) sepals, and (3) petals have been much debated without being definitely settled. They are sometimes referred to as (1) bracts, pedicellar bracts, lateral bracts, lower bractlets, or lower bracteoles; (2) upper bractlets, upper bracteoles, or involucral bracts; (3) sepals or tepals.

Important literature

Eriksson, R. 2004. Basellaceae. In: N. Smith et al. (eds), Flowering plants of the Neotropics, pp. 44-45, Princeton University Press, Princeton.

Eriksson, R. 2007. A synopsis of Basellaceae. Kew Bulletin 62: 297-320.

Sperling, C. R. 1987. Systematics of the Basellaceae. Unpublished Ph.D. dissertation, Harvard University, Cambridge.

Sperling, C. R. & Bittrich, V. 1993. Basellaceae. In: K. Kubitzki et al. (eds), The families and genera of vascular plants 2: 143-146, Springer-Verlag, Berlin.

How to cite

Eriksson, R. (2009). Neotropical Basellaceae. In: Milliken, W., Klitgård, B. & Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics. http://www.kew.org/science/tropamerica/neotropikey/families/Basellaceae.htm.