Cuscuta acuta

Nomenclature

Accepted name/Authority/Place of publication: 

Cuscuta acuta Engelm. in Trans. Acad. Sci. St. Louis 1: 497. 1859

Description

Habit: 
Annual parasite; stems 0.2-0.3 mm, yellow-orange.
Inflorescences: 
Dense umbelliform, confluent; pedicels 0.6–3.0 mm; bracts 1 at the base of clusters and 0–1 at the base of pedicels, 1.5–2.8 mm long, triangular-ovate, margins entire, apex acuminate.
Flowers: 
5-merous, 2.5–3.6(–4.0) mm, membranous, white when fresh, creamy-brown when dried; papillae absent, laticifers evident in the bracts, calyx, corolla, tips of infrastaminal scale fimbriae, and ovary, isolated or in rows, ovoid to elongate; calyx 1.6–2.3(–2.6) mm, straw-yellow to brown, not reticulate or shiny, campanulate, longer than corolla tube, divided ca. 2/3 the length, tube 0.4–0.8 mm, lobes (unequal) 0.7–1.5 mm, 12 not basally overlapping, ovate-triangular, not carinate, margins entire, apex acuminate; corolla 1.8–3.3(–3.8) mm, tube 0.9–1.7 mm, campanulate, lobes 0.9–1.9 mm, initially erect, later reflexed, ca. as long or slightly longer than the tube, ovatelanceolate, margins entire, apex acute to acuminate, straight; stamens exserted, shorter than the lobes, anthers 0.33–0.40 × 0.20–0.25 mm, broadly ovate to oblong, filaments 0.4–0.7 mm; infrastaminal scales extremely thin, 0.9–1.7 mm long, equaling the tube, bridged at 0.15–0.30 mm, obovate to oblong, uniformly dense-fringed, fimbriae 0.15–0.30 mm; styles 0.4–1.1 mm, shorter or equaling the ovary, slightly subulate at the base, filiform in the rest.
Fruits: 
Capsules indehiscent, 1.7–2.5 × 0.9–1.4 mm, globose-depressed, thickened around the moderate interstylar aperture, translucent, surrounded by the withered corolla.
Seeds: 
4 per capsule, 0.7–1.2 × 0.7–1.0 mm, subround to round.
Author: 
Mihai Costea
References: 

Austin, D.F. 1982. 165. Convolvulaceae. Pp. 1–98 in: Harling, G. & Sparre, B. (eds.), Flora of Ecuador, vol. 15. Göteborg, Stockholm:University of Götenborg, Riksmuseum.

Costea,M., S. Stefanović. 2010. Evolutionary history and taxonomy of Cuscuta umbellata complex (Convolvulaceae): evidence of extensive hybridizationfrom discordant nuclear and plastid phylogenies. Taxon 59: 1783–1800.

Engelmann, G. 1859. Systematic arrangement of the species of the genus Cuscuta with critical remarks on old species and descriptions of new ones. Trans. Acad. Sci. St. Louis 1: 453–523.

Yuncker, T.G. 1932. The genus Cuscuta. Mem. Torrey Bot. Club 18: 113–331.

Biogeography, Ecology and Natural History

Distribution: 

South America: Galapagos Islands and the Pacific Coast of Ecuador and Peru.

Ecology: 

Hosts: Alternanthera, Coldenia, Boerhavia, Euphorbia, Ipomoea, Pectis, Portulaca, Rhynchosia and Tribulus;elevation

40–160 m.

Author: 
Mihai Costea
Classification: 

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