Dalea urceolata var. tripetala

Rupert C. Barneby

29c.  Dalea urceolata Greene var. tripetala (P. G. Wilson) Barneby

(Plate XLIX)

Stems usually erect, but branched either from near base or beyond middle; leaflets mostly 6-13 pairs; petals 3; stamens 5-7, five perfect, the rest variably diminished or reduced to rudiments. — Collections: 9 (iv).

Pine-forest, sometimes with bunch-grasses or on pedregal, descending through the oak-pine belt to its lower edge, 1845-2550 m, locally plentiful on the s. slope of the Neo-Volcanic belt and margins of Balsas Depression from Volcan Colima, Jalisco, e. to s. Mexico and Morelos. — Flowering September to December. —Material: Jalisco. Zapoltiltic: n. slope Volcan Colima, McVaugh 13,564 (MICH). Michoacan. Zita- cuaro: Zitacuaro to Los Macheros (type). Anguangueo: Anguangueo, Paul Duke of Wiirtemburg in 1830 (M). Uruapan: s. of Carapan, Ripley & Barneby 14,088 (CAS, DS, GH, MEXU, MICH, NY, US), 14,845 (CAS, DAO, NY). Mexico. Otzoloapan: Cerro del Pinal, Matuda 31,776, p. p. (mixed with D. obreniformis, US). — : Oxtitil- pan, between Toluca and Temascaltepec, W. L. Graham 1271 (MICH, p. p.). Morelos. Huitzilac: Tres Cumbres, Ripley & Barneby 14,528 (NY); Cuernavaca: 4 mi n.-e. of Cuernavaca, Ripley & Barneby 14,539 (CAS, NY, US).

Dalea urceolata Greene var. tripetala (P. G. Wilson) Barneby, stat. nov., based on Petalostemon tripetalus (3-petalled) P. G. Wilson, Kew Bull. 1958: 159. 1958. — "Mexico. State of Michoacan: District of Zitacuaro, Zitacuaro to Los Macheros... 11 Oct. 1938, G. B. Hinton 13351." — Holotypus, K! isotypi, NY, UC, US (mixed with D. reclinata), W!

The var. tripetala was the first discovered (1830), and the last described (1938), but is now the best known form of D. urceolata. The epithet tripetala, meaningful in Petalostemon, is here only descriptive, not diagnostic, the flower being essentially like that of var. urceolata in everything but the reduced androecium. In general the individual plant of var. tripetala is more vigorous than the average var. urceolata, perhaps due to the higher rainfall and more benign autumn climate of its home. The calyx tends to be a little less distended than that of var. urceolata; on this point see further under D. exserta.

References: [Article] 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.

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