Monographs Details: Errazurizia rotundata (Wooton) Barneby
Authors:Rupert C. Barneby
Authority: Barneby, Rupert C. 1977. Daleae Imagines, an illustrated revision of Errazurizia Philippi, Psorothamnus Rydberg, Marine Liebmann, and Dalea Lucanus emen. Barneby, including all species of Leguminosae tribe Amorpheae Borissova ever referred to Dalea. Mem. New York Bot. Gard. 27: 1-892.
Family:Fabaceae
Synonyms:Parryella rotundata Wooton, Dalea nummularia M.E.Jones, Psorothamnus polydenius var. jonesii Barneby
Description:Species Description - Low, tortuously woody, resinously aromatic shrublets up to 3.5 dm tall and 1 m or more diam, reportedly rhizomatous, with gnarled, grayish-brown trunks up to 1 cm thick, repeatedly branched upward, the foliage and young stems densely strigulose- pilosulous with subappressed and narrowly ascending hairs up to 0.3-0.4 mm long (sometimes a few longer contorted hairs at base of leaves), cinereous or canescent, the stems, leaf-stalks, and lower face of leaflets charged with many prominent, orange or livid, grain- or prickle-shaped glands; stipules dimorphic, those subtending developed leaves 0.5-2.5 mm long, narrowly triangular to subulate, purplish-brown and distally glabrate, deciduous, charged at base and apex with 1 or more grainlike glands, those of inhibited axillary short-shoots closely imbricated to form globose buds; post- petiolular glands often present, nipple- or thorn-shaped, not regularly situated behind each petiolule; leaves 3-14 cm long, subsessile, with stiffly marcescent, narrowly green- margined, dorsoventrally flattened rachis and 14-30 pairs of suborbicular to oblong- obovate, obtuse or shallowly emarginate, dorsally keeled but flat, minutely gland- apiculate leaflets 1-8 mm long, these conspicuously but very gradually diminishing upward along the rachis, the terminal one smallest, elevated beyond the last pair, the larger ones pinnately nerved; peduncles terminal to branchlets of current year, 0-1 cm long; spikes shortly but rather loosely 6-15-flowered, the axis 4-15 mm long; bracts deciduous, narrowly lance-acuminate or subulate, 1.6-2.5 mm long, distally glabrate and glandular; calyx 5-6.5 mm long, at first narrowly later broadly vase-shaped, thinly pilosulous externally, densely pilosulous internally around the subsymmetrical orifice, the hypanthium 1.4-2 mm deep, the tube 3.5-4.2 mm long, prominently 10-ribbed and charged between the ribs with 1 often irregular row of 2-5 prominent glands, the oblong-obovate, obtuse or gland-apiculate teeth of nearly equal length (or the dorsal one slightly longer), 1.5-2.3 mm long, at anthesis erect, in fruit recurved; banner (often absent) oblanceolate, subacute to emarginate, shallowly boat-shaped but neither involute nor revolute at apex, pale yellow fading reddish, 5-5.4 mm long, 1.5-2.1 mm wide, thinly pubescent dorsally above middle; androecium (7) 8.5-12 mm long, the filaments united into a tubular sheath 3.5-4 mm long, free for (3.5) 5-8 mm, distally greenish-yellow, the connective glandless, the bright yellow anthers 1-1.3 mm long; ovules 2, not exactly collateral; pod ellipsoid or obovoid-ellipsoid, a trifle compressed, 9-11 mm long, cuneate at base, more abruptly contracted at apex into the persistent style-base, thick-carinate below the style, the valves densely strigulose and charged with many small grainlike, red or livid glands, becoming papery, rugulose; seed ellipsoid, subcompressed, (4.6) 5-7 mm long, (2.7) 3-3.7 mm wide in profile, 2-2.5 mm thick, the testa castaneous, lustrous.— Collections: 8 (iii).

Distribution - Rimrock and ledges of cliffs, on red or white sandstone, sometimes engulfed in drift-sand, 1350-1500 m (4500-5000 ft), very local, known only from two small areas on creeks flowing to the Little Colorado River in Coconino and Navajo counties, Arizona. - Flowering April and early May, fruiting in June.

Discussion:

(Plate II)

An extraordinary plant, notable for the long, multifoliolate leaves which suggest the fronds of Notholaena sinuata (Lag.) Kaulf., the usually apetalous flowers with their tassel of long-exserted stamens, and the relatively large spotted pod, not unlike that of Psorothamnus arborescens. Deaver reports that on the plateau above Moenave village the plants form rings, as though connected by subterranean stolons issuing from a dead central parent, but I could not confirm this on the cliff ledges at Willow Springs, where the plants form discrete rounded bushes, often wider than tall. Mahler (1965) found the pollen to be more like that of Parryella filifolia than that of other Errazurizias, suggesting that the species was placed originally in its proper genus. It seems conceivable that E. rotundata arose as a hybrid between Parryella and Psorothamnus, of which it has essentially the calyx and pod. Perhaps it should form a monotypic genus, but the multiple resemblances to other species of Errazurizia form a substantial basis for the current status.

The plant from northern Arizona (Petrified Forest, Apache County, Harrison 5532, US) reported by Kearney & Peebles (1942, p. 452) as intermediate between Parryella filifolia and P. rotundata is nothing more than a form of P. filifolia with leaflets slightly wider than average.

Distribution:United States of America North America| Arizona United States of America North America|

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