Dalea jamesonii

  • Title

    Dalea jamesonii

  • Authors

    Rupert C. Barneby

  • Scientific Name

    Dalea jamesonii (J.F.Macbr.) J.F.Macbr.

  • Description

    76.  Dalea jamesonii (Macbride) Macbride

    (Plate LXXVIII)

    Slender sparsely leafy shrubs up to 1.5-2 m tall, the old stems glabrate fuscous, the young branchlets smooth or remotely low-tuberculate, silky-strigulose with fine subappressed hairs up to 0.2-0.4 mm long, the foliage green, the leaflets smooth and glabrous above, paler, silky-strigulose and densely tuberculate beneath; leaf-spurs 0.6-1.6 mm long; stipules narrowly subulate, 1.5-4.5 mm long, strigulose dorsally; intrapetiolular glands 2, small, obtuse; post-petiolular glands larger, protuberant; leaves shortly petioled, the primary cauline ones 2-4 cm long, with narrowly margined, punctate rachis and 3-5(6) pairs of broadly oblanceolate to narrowly obovate, subacute or obtuse and apiculate, gland-mucronulate, flat or marginally involute to loosely folded leaflets 7-12 mm long, the terminal leaflet sessile, the uppermost leaves smaller, with 2-3 pairs of shorter leaflets; peduncles leaf-opposed and terminal to branchlets, (1) 1.5-6 cm long; racemes loosely (6) 9-30 (35)-flowered, the flowers spreading or subsecundly nodding, the silky-strigulose axis 1.5-4 cm long; bracts early deciduous, ovate, short-acuminate, 4-5.5 mm long, firm throughout, dorsally strigulose and thinly verruculose; pedicels erect, 0.7-1.5 mm long, densely silky- villosulous; calyx at anthesis 7-7.7 mm long, the basally constricted and oblique tube 4.4-4.7 mm long, a trifle accrescent in age, firm, externally glabrous, golden-brown or atrocastaneous and vernicose, bluntly ribbed and shallowly pleated, the broad intervals charged with usually 1 row of 4-6 elliptic golden glands, the teeth and orifice silky-villosulous with ascending hairs up to 0.4-0.6 mm long, the teeth subequal or the dorsal one a trifle longer, subulate from a deltate-triangular base, gland-spurred and -tipped, the dorsal tooth 2.6-3 mm long (1.4-2 mm shorter than tube); petals bicolored, the greenish-white, copiously gland-sprinkled blade often blue-margined laterally at base, the epistemonous ones intense purple-blue, perched below middle of androecium (2.5-5 mm above hypanthium), glandless or the keel (like the banner) gland-tipped; banner 7.8-10.5 mm long, the claw 3.6-5 mm, the suborbicular-cordate blade 5.6-6.7 mm long, 6.8-7.4 mm wide, the basal lobes incurved but not adherent, the shallow comet opening ventrally; wings 8.2-9.6 mm long, the claw 1.8-3 mm, the obliquely lance-elliptic blade 7.3-7.7 mm long, 3-3.2 mm wide, the reflexed auricle large; keel 9.5-12.5 mm long, the claws 2.3-4.7 mm, the narrowly elliptic blades 7.5-9 mm long, 3.2-3.4 mm wide; androecium 10-merous, 9.5-12.5 mm long, the longer filaments free for 3.8-4.5 mm, the connective gland-tipped, the bluish anthers 0.9-1.1 mm long; pod ± 4.5 mm long, obliquely triangular in profile, the style-base terminal, the prow slenderly carinate, the valves hyaline and glabrous in lower thence thinly papery, villosulous, and sparsely gland-sprinkled; seed ± 2.8 mm long. — Collections: 6 (o).

    Thickets and brushy hillsides, 2100-3200 m, very local, known with assurance only from the upper valley of Rio Paute, between Cuenca and Azogues and vicinity, in Canar and Azuay, Ecuador. — Flowering September to February, perhaps through the year .—Material: Canar: Azogues, Rose & Rose 22,790 (NY, US). Azogues to San Marcos, F. Prieto P-180 (NY, UC). Azuay: Gualaseo (typus). Rio Paute e. of Cuenca, M. A. Giler 16 (NY). Rio Paute "near Quito", Jameson s. n. (K, herb. Benth., herb. Hook.). "Colombia", herb. Muds. (US).

    Dalea jamesonii (Macbr.) Macbr., Candollea 7: 223. 1937, based on Parosela jamesonii (William Jameson, 1796-1873) Macbr., Field Mus., Bot. 4: 112. 1927. -"ECUADOR: Guaceo [= Gualaseo], Prov. of Cuenca, Sept., 1864, Jameson..." — Holotypus, US! isotypus (Jameson 93), K! clastotypus (fragm.), F!

    The only Andean dalea with pedicelled flowers, D. jamesonii is a small, awkwardly branching, sparsely leafy shrub, notable for the externally glabrous, vernicose, shorttoothed calyces and long, narrow keel of exceptionally dark and vivid blue coloring. The fruticose dalea common in and near the range of D. jamesonii is D. coerulea, similar in form and color of the petals, but sharply marked by its spiciform inflorescence and long, plumose calyx-teeth. The presence of pedicels is probably in most cases a primitive character in Dalea, but perhaps not in D. jamesonii, which suggests a specialized derivative of ser. Coeruleae rather than a relic species.