Astragalus Wootoni var. Candollianus

Essentially as in var. Wootoni except for the villosulous vesture and few- flowered racemes; leaflets often slightly more numerous, up to 23; pod loosely strigulose or in age (? sometimes truly) glabrous except for a line of hairs along the ventral suture.—Collections; 14 (i); representative: Parry & Palmer 173 (GH, NY); Schaffner 187 (NY); Rose & Hough 4558 (US); Arsène 10,061 (NY); Ripley & Barneby 13,463 (NY, RSA).

Dry hills, plains, valley floors, ± 2900-8200 feet, apparently not common, southcentral Mexico (Puebla and Valley of Mexico) west to Michoacán, north to San Luis Potosi and perhaps western Coahuila.—Map No. 119.—April to August, sometimes again from July to November.

Astragalus Wootoni var. Candollianus (Kunth) Barneby in Amer. Midl. Nat. 41: 498. 1949 ("Candolleanus"), based on Phaca Candolliana (Augustin Pyramus de Candolle, 17781841, one of the first systematic students of Astragalus) Kunth in H. B. K., Nov. Gen. & Sp. (folio) 6: 387, Tab. 586. 1824 (exclus. syn. Candoll.).—"Crescit in monte ignivomo Jorullo, alt. 480 hex.".—Typus, collected by Humboldt and Bonpland in 1803, P (herb. Humb.)! isotypus, P (herb. Bonpl.)! phototypus, labeled "Jorullo, donn6 par M. A. Bonpland," US!— Astragalus Candollianus (Kunth) Sheld. in Minn. Bot. Stud. 1: 140. 1891 (non A. Candolleanus Royle ex Bth. in Royle, 111. Himal. 199. 1835). A. triflorus var. Candollianus (Kunth) Jones in Proc. Calif. Acad. Sci. II, 5: 637. 1895 ("Candolleanus").

Phaca zacatecana (of Zacatecas) Rydb. in N. Amer. Fl. 24: 352. 1929.—"Casualidad, Zacatecas, April 26, 1892, M. E. Jones... "—Holotypus, NY! isotypi, MO, POM (Jones 146, 2 sheets), US! (non A. zacateconus (Rydb.) Barneby).

The var. Candollianus is not set off from its commoner relative var. Wootoni by any single differential character consistently correlated with a southern origin. It is rather the combination of villosulous vesture with small, often glabrescent pods and few-flowered racemes which serves to mark the whole southerly population as distinct. Humboldt’s plant is said to have a truly glabrous ovary (not checked) and must have come from below 3000 feet elevation, but there is no subsequent collection from below 5000 feet and none with a truly hairless gynoecium. In the Valley of Mexico the pod is nearly hairless at maturity, but traces of pubescence persist along the ventral suture even at the fully ripe stage (cf. Arsène 10,061, NY). Ordinarily the pod is thinly and loosely strigulose over the whole surface. The var. Candollianus was collected first late in the XVIII century by Sessé or his collaborators in Mexico (herb. Sessé & Mociño 3750bis, MA).

The validity of the epithet Candollianus as applied to our plant is open to challenge, since Kunth in the protologue of P. Candolliana identified his species with the Peruvian P. triflora DC. (Astragalogia, Pl. 1. 1802). It would be possible to regard P. Candolliana as an illegitimate substitute, but I agree with Johnston (1947, p. 392) that Kunth’s name should be reserved for the plant which he actually saw and described, whereas A. triflorus (DC.) Gray (Pl. Wright. 2: 45. 1853) is available for the Peruvian species. Gray was misled by Kunth and by DeCandolle himself (Prod. 2: 74. 1825) into believing the North and South American species conspecific, and in the first instance employed the combination A. triflorus in the sense of our A. Wootoni. If Johnston’s opinion proves unacceptable, we can perhaps conserve the epithet in the present sense and rank by tracing it no further back than A. triflorus var. Candollianus Jones (1895). Following Gray, the majority of botanists up to recent times have treated A. Wootoni (sens, lat.) under the name A. triflorus, although it should not be overlooked that Gray himself (1864, p. 214) subsequently quoted the Candollian basionym as a doubtful synonym of his A. triflorus (our var. Wootoni). The consequences of the taxonomic and nomenclatural confusion surrounding the two names Phaca triflora and P. Candolliana are more absurd than interesting. Sheldon attempted to pass off a new A. triflorus (DC.) Sheld. (non Gray) for the Peruvian plant and a new A. Candollianus (Kunth) Sheld., twice over a later homonym, for the Mexican one. And in order to squeeze his North American "A. triflorus" into the original Peruvian Phaca triflora, Jones resorted to a baseless accusation of inaccuracy on DeCandolle’s part, stigmatizing the beautifully exact figure in Astragalogia as a product of fancy. The true A. triflorus is only superficially similar to .4. Wootoni, differing in its connate stipules, few leaflets, and smaller, less swollen pod.