Dalea eriophylla

  • Title

    Dalea eriophylla

  • Author(s)

    Rupert C. Barneby

  • Scientific Name

    Dalea eriophylla S.Watson

  • Description

    122.  Dalea eriophylla Watson

    (Plate CX)

    Diminutive, intricately branching, round-topped shrublets 1-3 dm tall, with scaly, finally nigrescent older branches, the densely leafy growth of the year not over 6 cm long, either finely white-tomentulose throughout with soft ± sinuous hairs or (var.) only the interior of the bracts and stipules tomentulose and the foliage green, the leaflets in either case punctate beneath; leaf-spurs 0.4-1 mm long; stipules ovate- triangular to triangular-subulate, 0.8-2.5 mm long, castaneous or livid, densely pilosulous either within or without, but not both sides; intrapetiolular glands 0; post-petiolular glands small, often immersed in wool; leaves 2.5-9 mm long, all palmately 3-folio- late, the margined, readily disjointing petiole (0) 1.5-4 mm long, the subsessile, obovate to broadly oblanceolate or linear-oblanceolate, obtuse, flat to tightly conduplicate leaflets 1.5-5.5 mm long; spikes terminal to branchlets, sessile and involucrate by upper stem-leaves, depressed-capitate, dense, without petals 8-10 mm diam, less than half as long; bracts deciduous, subdimorphic, the outermost broadly rhombic- ovate or flabellate, apiculate, 3-4 mm long, the interfloral ones rhombic-spatulate, about as long, all ± livid and gland-tuberculate dorsally, tomentulose on one side but not on both; calyx 4.5-5.5 mm long, densely tomentulose or glabrous externally, the tube 2.2-2.7 mm long, its orifice somewhat recessed behind banner, the ribs castaneous or pallid, the rather firm intervals charged with 1 row of 1-4 minute transparent glands, the lanceolate, minutely gland-spurred teeth 2.1-3 mm long (0.4 mm shorter to 0.5 mm longer than tube); petals bicolored, the banner opening whitish with yellow eye, soon rubescent, charged with few glands and gland-tipped, the epistemonous ones perched well below middle of androecium (± 1.1-2.5 mm above hypanthium), pink- purple, at least the keel gland-tipped; banner 4.6-6.3 mm long, the claw 1.8-3 mm, the almost erect, deltate-cordate blade 2.4-3.5 mm long, 3.2-3.8 mm wide, recessed at base into a shallow cornet; wings 4.6-6.7 mm long, the claws 1.3-2.3 mm, the elliptic-oblong blade 3.7-5.1 mm long, 1.5-2.4 mm wide; keel 5.4-7.6 mm long, the claws 2-2.7 mm, the broadly oval-elliptic blades 3.7-5.8 mm long, 2.2-3.6 mm wide; androecium 10-merous, 6-7 mm long, the longer filaments free for 1.6-2.2 mm, the connective minutely gland-tipped, the anthers 0.5-0.65 mm long; pod not seen.

    A singular little dalea, instantly recognized by its diminutive shrubby form, trefoil leaves, and sessile heads of small pink and pale yellow flowers. It has no obviously close relatives, but in a general way suggests a reduced and condensed version of D. dorycnioides. The vesture (when present) is similar but the stems of D. eriophylla are not verru- culose and the interfloral bracts are deciduous by anthesis. Deciduous bracts are common to D. eriophylla and the sometimes associated D. greggii, but the latter differs greatly in its procumbently arched, tip-rooting stems, more numerous leaflets, and silky rather than woolly vesture.

    Known stations for D. eriophylla are few and far between and next to nothing is on record about its ecology. Near Galeana the plants were seen only on gypseous formations, and as gypsum is prevalent in the surface layers over much of the known range of the species, it may well turn out to be an obligate gypsophyte. Apart from the extraordinary variant described below as var. frankenioides, the species is essentially monomorphic.