1. Sphenocleaceae Baskerville
Gooseweed Family
J. Richard Carter
Jordan C. Jones
Herbs, annual. Stems mostly branched. Leaves alternate, estipulate, petiolate; blade: margins entire, often undulate, venation pinnate. Inflorescences terminal spikes. Flowers 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. Fruits capsules (pyxides), ± obconic, proximally laterally compressed and wedge-shaped, chartaceous, lustrous, dehiscence circumscissile; lids ± flat, discoid, subcoriaceous, covered by persistent, ± connivent, appressed calyx lobes. Seeds 100+, tan, oblong, ± lustrous, alveolate; endosperm cellular; embryos straight, filling the seed.
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).
SELECTED REFERENCE Rosatti, T. J. 1986. The genera of Sphenocleaceae and Campanulaceae in the southeastern United States. J. Arnold Arbor. 67: 1–64.
