Small desert shrubs (to 1 m tall), pubescent and charged almost throughout with prominent or superficial glands; leaves pinnate, the leaflets broad, obovate-suborbicular; inflorescence spicate, the flowers subtended by a bract and often a pair of sessile glands representing bracteoles; calyx deeply campanulate, 10- or by low bifurcation of the dorsal rib 11-nerved, the nerves not anastomosing distally into closed arches, the teeth herbaceous, oblong-obovate, pubescent within; petals 5 or (sect. Exostemon) either 0 or 1, all inserted on hypanthium rim, marcescent, of about equal length, not much longer than calyx, the banner not differentiated into blade and claw, usually pubescent dorsally; wings and keel either all separate and similar, oblanceolate, obscurely auricled, or (E. multifoliolata) the keel-blades differentiated from the claws and lightly adherent by their narrowly imbricate outer edges; androecium 9- or 10- merous, monadelphous; connective glandless; pollen-grains (Mahler, 1965, fig. 2, K-L, fig. 3, A-D) 3-colporate, operculate or not; style stout or slender, sometimes charged below the often capitately enlarged stigma with a prominent gland; ovules 2, not exactly collateral, only 1 maturing; pod exserted from marcescent calyx and apparently falling tardily with it, obovoid, subcompressed, prominently gland-sprinkled; seed subcompressed, (3) 4-7.5 mm long, the hilum sunk into a little pit. — Spp. 4, disposed in 3 sections, discontinuously dispersed over deserts of w. North and South America, 2 around the Gulf of California and Pacific Baja California, 1 in Chile, 1 in n. Arizona.
Errazurizia Philippi, An. Univ. Chile 1872. — Sp. unica: E. glandulifera Phil. = (syn. tax.) E. multifoliolata (Clos) I. Jtn.
The four species of Errazurizia are separated one from the next by wide morphological and geographical discontinuities; each has its idiosyncratic facies and all are internally uniform. They seem to be static, probably terminal products of a primitive Amorpheous stock. Within the tribe the genus Errazurizia forms a link between Eysenhardtia, which has a similarly organized, whitish or yellowish flower, and the more dalea-like Psorothamnus, the flower of which is papilionate and purple. In fruit Errazurizia is similar enough to the large-seeded species of Psorothamnus to have been classified by Watson in a heterogeneous sect. Xylodalea which united elements of both genera. The incipiently papilionate corolla of Chilean E. multifoliolata makes some approach to that of Psorothamnus, but the similarity is most easily explained, in the circumstances, as an instance of convergence, all other characters of the species pointing to a close kinship with E. megacarpa.
The following account is largely derived from an earlier paper (Barneby, 1962), based in turn on work by Johnston (1924) and, for the Sonoran Desert species, by Wiggins (1940). Since I transferred the anomalous E. rotundata from Parryella a comparative study of the pollen (Mahler, 1965) of all four species has shown that this may be an alien element in Errazurizia, more closely related to Parryella in which it was first described. The significance of the palynological data needs corroboration from other disciplines before any final disposition can be made of E. rotundata. In the first place chromosome counts for all species of Errazurizia are urgently required. Seeds of E. rotundata collected for this purpose were heavily infected by bruchid beetle-larvae, which are present in many herbarium specimens of the other species also. But this difficulty should be easily overcome.
The name Errazurizia, a curious one to the Anglo-Saxon eye, commemorates a prominent Chilean family of Basque extraction. Since early days of Chile’s independence the gifted Errazuriz have given their country a succession of poets, writers, bishops, statesmen, and several presidents of the republic.