Dalea pazensis

  • Title

    Dalea pazensis

  • Authors

    Rupert C. Barneby

  • Scientific Name

    Dalea pazensis Rusby

  • Description

    88.  Dalea pazensis Rusby

    (Plate LXXXVIII)

    Slender shrubs and subshrubs up to 0.6-2 m tall, often with a single trunk up to 8 mm diam, openly paniculate- or cymose-branching distally, the glabrate old wood brown and furrowed, the young leafy branches stramineous to pinkish-brown or livid- castaneous, at least distally charged with many low glands, finely pilosulous nearly throughout with narrowly ascending, subappressed, or sometimes a few irregularly spreading hairs up to 0.25-0.5 mm long, the foliage green or when young subcinerous, the leaflets pubescent both sides, often a little more densely above than beneath, closely punctate dorsally; leaf-spurs 0.6-2 mm long; stipules narrowly subulate, subsetiform, or narrowly lance-caudate, early becoming dry and fragile, (1.2) 2-4.5 (6) mm long, pilosulous at least within, commonly glandular externally; intrapetiolular glands 2, small but prominent, sometimes spiculiform; post-petiolular glands conic or prickle-shaped, prominent; leaves short-petioled, the main cauline ones (3) 4-8 cm long, drought-deciduous and often all lost from specimens at late anthesis, with narrowly margined, gland-sprinkled rachis and 7-11 pairs of oblong-elliptic to ob- lanceolate, obtuse or acute and sharply gland-mucronulate, flat or loosely folded leaflets up to (6) 7-13 (15) mm long, the leaves of barren or terminally flowering axillary branchlets shorter, with ±4-8 pairs of smaller leaflets, the terminal one usually stalked and a trifle larger than the last pair; peduncles (0) 0.5-7.5 cm long; spikes moderately dense, in bud ovoid-pyramidal becoming cylindroid, amentiform, including bracts but without petals or androecia 10-14 mm diam, the ascending flowers loosely contiguous, the densely pilosulous axis becoming (1) 1.5-8 (14) cm long; bracts persistent, 4-6.5 mm long, subhomomorphic (the lowest sometimes firmer and longer- tailed), the ovate-oblong navicular body loosely clasping the calyx, 2.7-4 mm long, in profile (0.9) 1-1.8 mm wide, with broad hyaline glabrous base and margins, otherwise thinly papery, livid-greenish, dorsally pilosulous and charged with prominent orange glands, abruptly contracted or attenuate into a subulate livid pilosulous tail 1-2.5 mm long; calyx 4.6-5.5 mm long, densely pilose-pilosulous with narrowly ascending, straight lustrous hairs up to 0.6-1.2 mm long, the tube (measured to dorsal sinus) 2.8-3.4 mm long, its mouth strongly oblique, the ribs slender, usually livid or castaneous, rarely pallid, becoming prominulous, the broad, almost flat intervals charged with 1 (the ventral pair with 2) rows of 2-6 small yellowish or colorless glands, the teeth unequal, the narrowly triangular dorsal one 1.6-2.5 mm long (0.7-1.6 mm shorter than tube), the lateral and ventral pairs progressively shorter and more broadly triangular, all usually gland-spurred and lividly gland-tipped; petals bicolored, the banner white but bluish-tinged around lower margins of gland-sprinkled blade, early rubescent, the epistemonous ones vivid cobalt or indigo blue, sometimes charged with a few small glands, the keel gland-tipped, perched well below middle of androecium (1.8-2.6 mm above hypanthium); banner 6.6-7.6 mm long, the claw 3.2-3.6 mm, the broadly flabellate or suborbicular-cordate blade 3.2-4.8 mm long, 4-5.2 mm wide, at base open or nearly so, the lobes incurved and adherent to form lateral pockets; wings 5.3-6.1 mm long, the claw 1.7-2 mm, the obliquely ovate blade 4.2-4.6 mm long, 1.9-2.5 mm wide; keel 7.6-9 mm long, the claws 2.6-3.5 mm, the broadly ovate-elliptic blades 4.9-6.3 mm long, 2.9-3.8 mm wide; androecium 8.2-10.2 mm long, the longer filaments free for 2.2-3 mm, the connective gland-tipped, the pale bluish anthers (0.55) 0.6-0.8 mm long; pod almost exactly deltate in profile, isotriangular, ± 2.7 mm long, the prow subfiliform, the style-base at comer, the valves hyaline and glabrous in lower thence papery, stramineous, pilosulous, gland- sprinkled; seed 1.9-2.1 mm long. — Collections: 25 (o).

    Dry rocky hillsides and stony washes, mostly 2250-3000 m, locally abundant along the e. rim of the Bolivian Plateau in Dptos. La Paz (s.-ward from Sorata), Cochabamba, and Sucre, descending rarely along Rio La Paz to the margins of Las Yungas at 1050 m. — Flowering October to June. — Representative: La Paz: Mandon 699 (BR, F, K, NY, US, W); Buchtien 554 (NY, US), 3194 (K, NY, US). Cochabamba: Steinbach 8753 (F, K, NY, US); Cardenas 640 (US); Balls 6227 (UC, US); Eyerdam 24,867 (F, K, UC). Sucre: Cardenas 640 (NY).

    Dalea pazensis (of La Paz) Rusby, Mem. Torrey Club 33: 18. 1893 (Pazensis").— "Near La Paz, 10,000 ft., 1890 (678)." — Holotypus, collected by Miguel Bang, NY! isotypi, GH, K, NY (2 sheets), US! — Parosela pazensis (Rusby) Macbr., Contrib. Gray Herb., New Ser. 65: 23. 1922.

    Parosela oblongifolia (with oblong leaflets) Rusby, Mem. N. Y. Bot. Gard. 7: 262. 1927. — "Espia 3500 feet, O. E. White, July 25, 1921 (no. 608)." — Holotypus, NY! isotypi, GH, US!

    A slender shrub, prone to lose its primary foliage during anthesis, but attractive nevertheless because of its relatively long and loose catkin-spikes of vivid blue and white flowers. It is often associated with and in form, size and color of the bracts and flowers closely resembles D. boliviana, but is a more erect, distinctly fruticose plant with stems 6-20 (not 1-4.5) dm long, longer leaves (mostly 4-8, not 1-3 cm), and slightly more numerous (mostly 7-11, not 4-8) pairs of leaflets. In habit D. pazensis resembles the allopatric Peruvian D. smithii, but this is quickly distinguished by its deciduous interfloral bracts. In southern Bolivia its range approaches that of the largely Argentinian D. elegans, like it in persistent bracts but different in the more numerous (mostly 10-19, not 7-11) pairs of leaflets, of which the uppermost form with the odd one a palmate, not a pedate trefoil.

    No marked variation can be recorded for D. pazensis. The type of P. oblongifolia, despite its origin on the east piedmont of the plateau more than 1000 meters below the main range of D. pazensis, does not differ materially. At Espia the species is associated with D. carthagenensis var. pilocarpa, which reappears at Sorata, again in company with D. pazensis, near 2600 meters. The species was collected first in 1846, by Thomas Bridges (K).