Sphenoclea zeylanica
Sphenocleaceae
chickenspike
gooseweed family
± terete, green, 2–10 mm diam. at mid stem, often proximally spongy and rooting from proximal nodes where submerged.
mostly branched.
petiole 0.3–2.7 cm;
blade 1–13.8 × 0.3–5.7 cm.
alternate, estipulate, petiolate;
blade: margins entire, often undulate, venation pinnate.
terminal spikes.
0.4–10.3 cm.
narrowly ovoid to cylindric, 0.5–10.5 × 0.3–1.3 cm.
calyx lobes broadly ovate to deltate, 1.2–1.5 × 1.5–1.8 mm, enlarging in fruit, obtuse to rounded, ± erose;
corolla caducous, 1.8–2.3 mm, lobes oblong, length 1–2 times tube, apex obtuse to acute, ± erose;
filaments 0.1–0.2 mm;
anthers 0.5 × 0.6 mm;
styles 0.3–0.4 mm;
stigmas 0.4 mm diam.
sessile, epigynous, actinomorphic;
calyx lobes 5, imbricate, connivent, proximally connate;
corolla short-tubular, lobes 5, alternate with calyx lobes, proximally connate;
stamens 5, alternate with corolla lobes, adnate to corolla tube;
filaments 0.1–0.2 mm;
anthers ± quadrate, 2-locular;
ovary inferior, 2-locular;
ovules 100+, anatropous;
placentation axile;
styles 0.2–0.3 mm;
stigmas discoid-capitate, depressed.
capsules (pyxides), ± obconic, proximally laterally compressed and wedge-shaped, chartaceous, lustrous, dehiscence circumscissile;
lids ± flat, discoid, subcoriaceous, covered by persistent, ± connivent, appressed calyx lobes.
sessile, 2–3 × 3–4 mm, lids 3–4 mm diam.
0.4–0.5 mm.
100+, tan, oblong, ± lustrous, alveolate;
endosperm cellular;
embryos straight, filling the seed.
= 24.
Sphenoclea zeylanica
Sphenocleaceae
Sphenoclea zeylanica is a common weed of rice fields and other wet disturbed sites in the coastal prairies of southern Louisiana and southeastern Texas. It occurs sporadically in other southeastern states, and its dispersal is correlated with rice agriculture. The earliest records in the United States were collected in Louisiana about 1850, where it was probably introduced as a contaminant of rice seed (J. R. Carter et al. 2014).
West African plants with shorter oblong spikes, pink corollas, and stamens with longer filaments are sometimes segregated as the endemic Sphenoclea dalzielii N. E. Brown (S. M. H. Jafri, http://www.tropicos.org/Name/ 5504127).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Genus 1: introduced; Asia, Africa; introduced also in Mexico, West Indies, Central America, South America.
Sphenoclea has commonly been included within Campanulaceae. H. K. Airy Shaw (1948), noting similarities with both Phytolaccaceae (habit, anatomy) and Primulaceae, treated it in monogeneric Sphenocleaceae. T. J. Rosatti (1986) also placed it in Sphenocleaceae, citing differences between Sphenoclea and Campanulaceae (for example, spicate inflorescences, circumscissile capsules, tetracyclic stomata, pericyclic stem sclerenchyma, cluster crystals, and absence of laticiferous phloem canals). Molecular evidence (B. Bremer et al. 2002) supports treatment in Sphenocleaceae, and that family in Solanales of the Lamiid clade (Angiosperm Phylogeny Group 2009).
A root exudate of Sphenoclea zeylanica has been shown to be an effective nematocide (C. Mohandas et al. 1981). In Java, nascent shoots are consumed as a condiment of rice, imparting a bitter flavor (H. K. Airy Shaw 1948), and it is intensively cultivated in Bali as a highly nutritious vegetable (I. W. A. Permadi et al. 2016). Sphenoclea zeylanica has been cited as an agricultural weed of rice in the southeastern United States (C. T. Bryson and M. S. DeFelice 2009) and in rice-growing areas throughout the world (T. J. Rosatti 1986). Herbicide-resistant biotypes of S. zeylanica have been reported in Asia (K. Itoh and K. Ito 1994).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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