Dalea cinnamomea

Title

Dalea cinnamomea

Author(s)

Rupert C. Barneby

Scientific Name

Dalea cinnamomea Barneby

Description

100.  Dalea cinnamomea Barneby

(Plate XCIII)

Slender, awkwardly branching shrubs up to 1-2.4 m tall, precociously flowering when suffruticose, the growth of the year rather densely leafy, densely and softly villosulous throughout with vertical or widely ascending hairs up to 0.4-1 (1.2) mm long, the young, virgately ascending, brown-purplish stems either simple or branched below middle, distally gland-verruculose and forking into a corymbose panicle of heads terminal to ± 2-7 branchlets, the young foliage ashen, in age greenish, the leaflets pubescent both sides, bright green beneath the vesture above, paler and punctate beneath; leaf-spurs very short; stipules linear-acuminate or -caudate, 1.5-4 mm long, verruculose, becoming dry and deciduous; intrapetiolular glands small, sometimes immersed; post-petiolular glands prominent, mammiform, orange; leaves subsessile, the main cauline ones divaricate or reflexed, 2-5.5 cm long, with narrowly margined, often incurved rachis and 9-15 pairs of rather crowded, oblong or oblong- obovate, obtuse and bluntly gland-mucronate or emarginate, mostly flat leaflets 4-11 mm long, gradually smaller upward, the uppermost leaves shorter, with fewer smaller leaflets; peduncles stout, 1-8 (10) cm long; spikes very dense, conelike, ovoid becoming ovoid-oblong, without petals 10-13 mm diam, the villosulous axis (1) 1.5-2.5 cm long; bracts persistent, rhombic-lanceolate, 4-6 mm long, the boat-shaped body submembranous, carinate dorsally, villosulous within and without, contracted into a lanceolate, gland-verruculose, livid, gland-tipped, sometimes glabrescent tail almost as long; calyx 4.7-6 mm long, villosulous with fine soft ascending hairs, the submembranous pallid tube thinly so, 2.5-3 mm long, the ribs slender, not prominent, the intervals charged with 1 (the ventral pair with ± 2) rows of 3-5 (7) honey-colored glands, the herbaceous teeth strongly unequal, the dorsal one lanceolate, (2.1) 2.4-3 mm long, the lateral and ventral pairs much shorter, separated by rounded sinuses, the forked nerves below them intramarginal; petals pale pinkish-brown fading cinnamon-brown, the banner gland-tipped, the remainder glandless, the epistemonous ones perched low on the androecium, 1.8-2.8 above hypanthium; banner 4.5-5.3 mm long, the claw 2-3 mm, the funnel-shaped, nearly erect blade 2.5-3 mm long, 3-3.4 mm wide, emarginate at apex, recessed at base into a cornet; wings 4.5-5.2 mm long, the claw 2.1-2.3 mm, the elliptic blade 3.1-3.4 mm long, 1.6-2 mm wide; keel 5.5-6 mm long, the claws 2.1-2.3 mm, the blades 3.5-4.1 mm long, 2-2.4 mm wide; androecium 10-merous, 7.2-8.6 mm long, the longer filaments free for 1.8-2.5 mm, the connective gland-tipped, the brown anthers (0.65) 0.75-0.9 mm long; pod (not seen mature) ± 3 mm long, triangular in profile, the style-base terminal, the valves hyaline and glabrous at base, thinly herbaceous, barbate, and gland-sprinkled distally.— Collections: 4 (ii).

Hot brushy hillsides on volcanic bedrock, often entangled with spiny Mimoseae, 1170-1500 m (3900-5000 ft), local, known only from the hill-country s. of Izucar de Matamoros in w. Puebla, and near Xochitepec in adjoining Morelos. — Flowering September to January. — Material: Puebla. Izucar de Matamoros: Matamoros, Miranda 2448 (MEXU); 7 mi s. of Izucar, Ripley & Barneby 14,568 (CAS, DAO, F, GH, MEXU, MICH, NY, UC, US). Morelos. Xochitepec, Lyonnet 869 (US).

Dalea cinnamomea (cinnamon-colored) Barneby, sp. nov., D. tomentosae (Cav.) Willd. ut videtur affinis, sed pube villosa nec sericea, foliorum majorum foliolis 9-15 (nec 2-5)-jugis sursum secus rachin decrescentibus, petalisque junioribus roseo-brun- nescentibus cito cinnamomeis insigniter diversa. — Frutices 1 - 2.4 m altae graciles undique patentim villosulae; folia caulina patula 2-5.5 cm, foliolis planis inferne punctatis 4-11 mm longis; inflorescentia laxe corymbosa, pedunculis terminalibus 1-8 cm longis; spica ovoidea strobiliformis absque petalis 1-1.3 cm diam; calycis tubus parce villosulus dente dorsali subaequilongus, dentibus aliis multo brevioribus; vexilli lamina basi in puteolum recessa; carinae laminae ± 3.5-4 mm longae. — PUEBLA. Izucar de Matamoros: 8 mi s.-e. of Izucar de Matamoros, nov 7, 1964, Ripley & Barneby 13,690. — Holotypus, NY; isotypi, CAS, GH, K, MEXU, MICH, NY, US.

An ungainly but interesting shrub, notable for its soft villous pubescence and hard eggshaped flower-spikes borne in loose, more or less corymbose panicles. The stems of young plants are virgate, herbaceous almost to the ground, but persist in the form of thin woody trunks bearing aloft succeeding generations of tender growth. In structure of calyx and petals D. cinnamomea resembles D. tomentosa and D. leucosericea, but differs from both in the quality of vesture, in the many leaflets, and in the extremely dense, conelike spikes. The paniculate arrangement of the inflorescence is emphatically unlike the narrow thyrse of the sympatric D. tomentosa var. psoraleoides, but not essentially different from that seen in the allopatric D. tomentosa var. mota, or sometimes in D. leucosericea. The color of the petals, suggesting a compromise between pink and brown or possibly pale yellow, has no match in Dalea, and the chemistry of the pigment would form an interesting subject of inquiry. It is a tempting hypothesis to derive D. cinnamomea from a cross between a pink-flowered and a yellow-flowered species, but there is no known candidate for the second role.

A single individual plant (Ripley & Barneby 13,709, CAS, NY) found near Tlaltizapan, Morelos, close to a colony of typical D. leucosericea, resembled D. cinnamomea so closely in habit and petal-color as to be taken for that species in the field, but is now interpreted as a probable hybrid involving D. leucosericea. More silky pubescence, barren axillary branchlets bearing short 7-11-foliolate leaves, and a less dense spike of more symmetrical calyces are all features suggesting this parentage.