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FNA | Family List | FNA Vol. 5 | Polygonaceae

10. Johanneshowellia Reveal, Brittonia. 56: 299. 2004.

Howell's-buckwheat [for John Thomas Howell, 1903-1994, California botanist and Eriogonum scholar]

James L. Reveal

Eriogonum Michaux [unranked] Puberula Rydberg, Fl. Rocky Mts., 211. 1917

Herbs, annual; taproot slender. Stems arising directly from the root, weakly erect to spreading, solid, not fistulose or disarticulating into ringlike segments, silky-puberulent. Leaves usually quickly deciduous, basal, rosulate; petiole present; blade obovate to rounded or somewhat reniform, margins entire. Inflorescences terminal, cymose; branches dichotomous or trichotomous at proximal node, otherwise dichotomous, not brittle or disarticulating into segments, round, silky-puberulent; bracts 3, connate proximally, triangular or linear to narrowly lanceolate, scalelike or somewhat leaflike, not awned, glabrous to puberulent. Peduncles absent. Involucral bracts obscure, in tight spiral of (3-)4(-7) distinct, oblanceolate to obovate lobes, bractlike, not awned. Flowers 4-7 per involucral cluster; perianth white or pale yellowish to rose or red, broadly campanulate when open, narrowly urceolate when closed, smooth or minutely pustulose abaxially, glabrous; tepals 6, connate 1/ 4 their length, monomorphic or slightly dimorphic, entire apically; stamens 9; filaments basally adnate, glabrous; anthers white to pale pink, oblong. Achenes included, light brown, not winged, 3-gonous, glabrous. Seeds: embryo curved.

Species 2 (2 in the flora): w United States.

With recognition of Johanneshowellia, all members of Eriogonum have their involucral bracts fused into a distinct, turbinate to campanulate or hemispheric, tubular structure. In Johanneshowellia, the four to seven, distinct, involucral bracts are arranged in a tight spiral. Each 0.5-1.2 mm, awnless, entire to deeply lobed bract subtends a flower-bearing pedicel. These involucral bracts are themselves usually obscured by inflorescence bracts that subtend each node. As a result, care must be taken to observe the true nature of the involucral complex. The genus is allied with Eriogonum subg. Oregonium.

1 Perianths minutely pustulose basally and along midribs, 1.5-2 mm in fruit; outer tepals narrowly ovate, slightly auriculate basally with slightly undulate-crisped margins in fruit; plants grayish to greenish, mostly densely silky-puberulent   1 Johanneshowellia puberula
+ Perianths smooth, 2-2.5 mm in fruit; tepals lanceolate, not auriculate basally, margins entire; plants reddish, thinly silky-puberulent   2 Johanneshowellia crateriorum

Lower Taxa


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