146a.  Dalea sericea Lagasca var. sericea

(Plate CXXXII)

Stems vertical or incurved, not humifuse; peduncles mostly longer than the stem’s leafy axis; flower relatively large, and calyx long-toothed (cf. key); androecium 8.5-11 mm long; n = 7 (Spellenberg, 1973); 2n = 14, 7 II (Mosquin). — Collections: 103 (xi).Dry rocky and gravelly hillsides, ascending into sunny openings or glades in oak or oak-pine forest, coming out n.-ward into grama grassland, mostly between 1450 and 2600 m (± 4830-8650 ft), widespread in temperate s. Mexico from around the w. and s. margin of the Meseta Central (w.-centr. Durango to Guanajuato, Valley of Mexico, centr. Puebla and adjoining Veracruz) s. through the Cordillera Neo-volcanica, Sierra Madre del Sur, and mountainous interior Oaxaca to the highlands of Chiapas, Guatemala, and Honduras. — Flowering July to January. — Representative: MEXICO. Durango: Palmer 800 (F, NY, UC, US); Ripley & Barneby 14,167 (DS, NY). Zacatecas: M. Rodriguez in 1966 (ENCB). Jalisco: Pringle 2799 (F, UC), 11,426 (F, L, MEXU). Guanajuato: typus of D. gracilis (vide infra). Queretaro: Waterfall 13,970 (F, OKLA). Michoacan: Hinton 13,425 (NY, UC); Ripley & Barneby 13,417 (CAS, NY, MEXU, US), 14,126 (CAS, DAO, NY). Mexico: Pringle 3182 (F, M, NY, UC, W, Z), 8999 (BR, ENCB, F, L, M, NY, UC, US, W); Ripley & Barneby 13,386 (CAS, MEXU, MICH, NY, US). Hidalgo: Moore & Wood 4860 (UC); Rose, Painter & Rose 1974 (NY, US). Puebla: Purpus 2478 (F, UC). Veracruz: Bourgeau 3174 (BR, P). Morelos: Ripley & Barneby 14,544 (NY). Guerrero: Hinton 14,772 (ARIZ, NY, W); E. W. Nelson 2179 (NY, US). Oaxaca: Ripley & Barneby 14,624 (DAO, NY, US), 14,629 (NY). Chiapas: Matuda 1968 (ARIZ, F, NY); Breedlove & Raven 13,092 (US). GUATEMALA. Alta Verapaz: von Turckheim 11-2048 (BR, F, L, W). Chimaltenango: Standley 57,967 (F). Guatemala: A. Rodriguez 1382 (F). Huehuetenango: Standley 65,842, 81,512, 81,945 (F). Jalapa: Steyermark 32,589 (F). Sacatepequez: Standley 61,741 (F). HONDURAS. Comayagua: L. & R. Williams 6281 (F). El Paraiso: A. Rodriguez 1782 (F). Morazan: Standley 15,237 (F).

Dalea sericea (silky) Lag., Gen. & Sp. Nov. 23. 1816. — "Habitat in Nov. Hisp. —No typus survives at MA, but the protologue traditionally accepted in the current sense. — Parosela sericea (Lag.) Rose, Contrib. U. S. Nat. Herb. 10: 105. 1906.

Dalea gracilis (slender) Kunth, Mimoses 166, PI. 48. 1819. — "Crescit in Regno Mexicano, prope urbem Guanaxuato, alt. 1700 hex." — Holotypus, P (herb. H. B. K.)! isotypus, labelled "D. pedunculata Bonpl.", P (herb. Bonpl.)! — Parosela gracilis (Kunth) Rose, Contrib. U. S. Nat. Herb. 10: 105. 1906.

Dalea alopecurus (fox-tail, of the spike) Sesse & Moc. ex G. Don, Gen. Hist. Diehl. Pl. 2: 223. 1832. — "Native of Mexico...(v.s. in herb. Lamb.)." — Holotypus not known to survive, but most probably it was an isotypus of Psoralea alopecurus S. & M. sold to Lambert by Pavon; cf. infra.

Dalea alopecurus "Ruiz & Pavon" ex Moric., Mem. Soc. Geneve 7: 250, PI. 8. (= Pl. Nouv. d’Amer. 10, Tab. VIII.). 1836. — "Hab. in Mexico, in las Cordilleras de Guchilapa [= Huitzilac, n. of Cuernavaca, Morelos]," the collector not mentioned. — Holotypus, Berlandier 1022, collected in oct 1827, G (labelled "Cord, de Guchilaque"); isotypi, G ("Cord, de Guchilapa"), OXF, P! paratypus, a Sesse & Mocino collection sent by Pavon as Dalea alopecurus, G! = isotypus of the next.

Psoralea alopecurus Sesse & Mocino, Fl. Nov. Hisp. 120. 1889. — "Habitat in Chilapae pratis [Guerrero]." —No holotypus so identified in herb. S. & M., although Nos. 2658, 2663, 2674 (F) belong here; presumed isotypi distributed by Pavon as "Dalea alopecurus", BM, G, P!

Variation immediately apparent in the material assembled here under the title of var. sericea is expressed primarily in growth-habit and stature. Along the western and southern Cordilleras, from Durango into Honduras, and locally on the Gulf slope in Veracruz, the plants are almost uniformly robust, consisting at maturity of one or few sutrdily erect, most commonly monocephalous stems that pass distally into a peduncle 2-5 dm long, seemingly continuous with the leafy axis. From root to spike the plant measures 5-12, rarely 15 dm in height. On the south edge of the Central Plateau, subject to a more arid climate, the average plant is relatively small and slender, with incurved-ascending, pliant stems passing into a peduncle about 1-2.5 dm long, this usually longer than the leafy portion. All of the material collected in Guanajuato, Hidalgo, and in the valley of Mexico conforms more or less closely to this lowly phase, beautifully portrayed by Kunth as Dalea gracilis, whereas the robust phase of wider dispersal corresponds with D. alopecurus S. & M. Generally the taller plant has thicker spikes of relatively large calyces, but there is no firm correlation between flower-size and habit. The pubescence of the alopecurus- phase tends to be looser and longer than that of the gracilis-phase, but the difference is elusive. Size of petals varies independently of the calyx (and hence of spike-diameter). While most of the specimens seen could be sorted artificially by size alone, the decision one way or another is highly arbitrary, and the problem is aggravated in the field by intra- populational variation. If Rydberg’s two categories corresponding with Parosela sericea and P. gracilis should, despite intergradation, be evaluated as geographic phases worth taxonomic notice, a vexatious problem of nomenclature will arise, for although D. sericea Lagasca is surely the oldest name available for the whole species, no holotypus has survived and the description is too short to indicate which phase of it was being described. Specimens of both were collected by Sesse and collaborators and must have been available in Madrid by 1816. It is tempting to suppose that Lagasca was actually describing the plant preserved in the Sesse herbarium as Psoralea sericea, but proof of this connection is hardly possible.

The banner of var. sericea shows interesting variations in form and color of the blade. This may be solid blue, blue with a white eye, or white except for blue bands around the outer and lower margins, the white part in any case turning reddish after fertilization of the flower. Ordinarily the blade is bluntly and shallowly three-lobed, with the central lobe commonly subacute or mucronulate. A race common locally in the Sierra Madre foothills west of Ciudad Durango differs from the norm in having a round, apically emarginate blade.