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FNA | Family List | FNA Vol. 5 | Polygonaceae

2. Dedeckera Reveal & J. T. Howell, Brittonia. 28: 245, fig. 1. 1976.

Eureka or July gold [for Mary Caroline DeDecker, 1909-2000, noted California conservationist]

James L. Reveal

Shrubs; taproot stout. Stems spreading, woody, hirsutulous; caudex absent; aerial flowering stems spreading, herbaceous, hirsutulous. Leaves usually persistent through anthesis, 1 per node, cauline, alternate; petiole present, blade narrow to broadly elliptic, margins entire. Inflorescences terminal, cymose; branches dichotomous, not brittle or disarticulating into segments, round, hirsutulous, each node with 1 short-pedicellate flower and 4-12 sessile or subsessile flowers; bracts 3-4 at proximal nodes and leaflike, 2-3 at distal nodes and scalelike, distinct, hirsutulous. Peduncles erect, slender. Involucral bracts obscure, in 2 whorls of 3 plus 2 lobes at proximal nodes, distinct, reduced to 2 lobes at distal nodes, not awn-tipped. Flowers 4-6 per involucral cluster, sessile or pedicellate; perianth yellow to reddish yellow, broadly campanulate when open, narrowly urceolate when closed, hispidulous abaxially; tepals 6, slightly dimorphic, those of outer whorl broader and longer than those of inner whorl, entire apically; stamens 9; filaments basally adnate, pilose basally; anthers yellow, oblong. Achenes, light reddish brown, not winged, 3-gonous, pubescent apically. Seeds: embryo curved. x = 20.

Species 1: California.

Dedeckera is rare but not endangered or threatened, primarily because most populations are in remote areas along sides of steep canyon walls. Most populations occur in areas managed by the Bureau of Land Management, the United States Forest Service, or the National Park Service. The plants rarely produce mature achenes (D. Wiens et al. 1989). The genus is allied to Eriogonum subg. Eucycla.


Nickrent, D. L. and D. Wiens. 1989. Genetic diversity in the rare California shrub Dedeckera eurekensis (Polygonaceae). Syst. Bot. 14: 245-253. Wiens, D. et al. 1989. Developmental failure and loss of reproductive capacity in the rare palaeoendemic shrub Dedeckera eurekensis. Nature 338: 65-67. Wiens, D., L. Allphin, D. H. Mansfield, and G. Thackray. 2004. Developmental failure and loss of reproductive capacity as a factor in extinction: A nine-year study of Dedeckera eurekensis (Polygonaceae). Aliso 21: 55-63. Wiens, D., C. I. Davern, and C. L. Calvin. 1988. Exceptionally low seed set in Dedeckera eurekensis: Is there a genetic component of extinction? In: C. A. Hall and V. Doyle-Jones, eds. 1988. Plant Biology of Eastern California. Los Angeles. Pp. 19-29. Wiens, D., M. DeDecker, and C. D. Wiens. 1986. Observations on the pollination of Dedeckera eurekensis (Polygonaceae). MadroƱo 33: 302-305.

Lower Taxon


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