Marina divaricata (Benth.) Barneby
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Authors
Rupert C. Barneby
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Authority
Barneby, Rupert C. 1977. Daleae Imagines, an illustrated revision of Errazurizia Philippi, Psorothamnus Rydberg, Marine Liebmann, and Dalea Lucanus emen. Barneby, including all species of Leguminosae tribe Amorpheae Borissova ever referred to Dalea. Mem. New York Bot. Gard. 27: 1-892.
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Family
Fabaceae
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Scientific Name
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Type
based on Dalea divaricata (spreading at wide angles, of the branches) Benth., Bot. Sulphur 12. 1844.— "Bay of Magdalena." — Holotypus, collected by Dr. Richard Brinsley Hinds, surgeon-naturalist aboard H. M. S. Sulphur, in Nov. 1839, K (herb. Benth.)! par
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Synonyms
Dalea divaricata Benth., Parosela divaricata (Benth.) Rose, Dalea anthonyi Brandegee, Parosela anthonyi (Brandegee) Rose, Dalea divaricata subsp. anthonyi (Brandegee) Abrams, Parosela variegata Rydb., Dalea variegata (Rydb.) Gentry
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Description
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Species Description - Perennial, suffrutescent becoming truly shrubby and up to 0.5-2 m tall, in dry, exposed places diffuse and twiggy, in sheltered canyons, washes, and open woodland becoming erect and bushy, commonly glabrous to the inflorescence but the leaf- rachis, the young branchlets and the leaflets of some upper leaves sometimes thinly pilosulous with spreading-incurved hairs up to 0.2-0.35 mm long, the purplish, glaucescent stems gland-verruculose, the foliage dark green or purpurascent, the leaflets lineolate above, punctate beneath, commonly gland-crenulate; leaf-spurs 0.5-1.5 mm long; stipules subulate or deltate-caudate, 0.7-2 mm long, livid, becoming dry and fragile; intrapetiolular gland globose or spiculiform; post-petiolular glands conical, prominent, orange or livid; main cauline leaves (drought-deciduous) 1-3.5 (4) cm long, short-petioled, the rachis very narrowly margined, the leaflets (6) 7-12 (13) pairs, oblong, oblong-obovate, or suborbicular, truncate to shallowly notched at apex, flat, thick-textured, 1-5 mm long; peduncles mostly leaf-opposed, 1.5-5 mm long; racemes at first conical becoming narrowly oblong-cylindric, moderately dense to quite loose and open, the flowers mostly 2-ranked when pressed, without petals ±7-10 mm diam, the glabrous axis becoming 1.5-6 (10) cm long; bracts deciduous, lance- acuminate or -caudate, firm, green or livid-castaneous, 3-5.5 mm long, glabrous or thinly pilosulous dorsally, charged on the back and margins with glands, often appearing fimbriolate; pedicels ascending, 0.3-0.7 mm long, charged at base and near apex with a pair of fusiform yellow glands; calyx 2.9-4.5 mm long, glabrous except for the thinly ciliolate orifice, the pleated tube 1.6-2.6 mm long, the ribs prominent but very obtuse and appearing ± spongy-thickened, the intervals little differentiated in texture, charged in the upper half with 1-3 small but prominent blister-glands, the teeth unequal, the dorsal one longest, lanceolate, 1.1-2.1 mm long (0.6 mm shorter to slightly longer than the tube), incurved at tip, the rest broader, ovate-triangular, a little shorter to half as long as the dorsal one; petals bicolored, the banner blue with a yellow, gland-sprinkled eye, the inner ones blue in the interior half, pallid or white externally, the keel inserted below middle of the androecial column; banner 2.5-3.4 mm long, the claw 1.5-1.7 mm, the reniform-emarginate to flabellate-cordate and acutish blade 1.5-2.2 mm long, 2-3 mm wide; wings 3.2-4.7 mm long, the claw 0.8-1.3 mm, the ovate to oblong-ovate, shortly auriculate blade 2.5-4.1 mm long, 1.4-2.7 mm wide; keel 5.3-6.8 mm long, the claws 1.6-2.3 mm, the broadly oval-obovate blades (4) 4.2-5 mm long, 2.4-3.1 mm wide; androecium 10-merous, 6-7.5 mm long, the longer filaments free for 2-2.7 mm, the pale blue anthers 0.5-0.6 mm long; pod 2.5-3 mm long, hyaline at base, charged above middle with 2 subvertical gland-crescents, glabrous; seed (little known) ± 2 mm long. — Collections: 31 (o).
Distribution and Ecology - Rocky washes and desert hillsides, ascending from coastal fog-desert at its n. limit into the oak-belt of the Cape mountains, reaching 1800 m (6000 ft) in Sierra de Laguna, apparently not uncommon along the west coast of Baja California Sur from Isla Magdalena s. to Cabo San Lucas and San Juan del Cabo, and on both slopes of the Cape mountains s. of lat. 24 ° N. — Flowering both in spring and fall, perhaps intermittently through the year.
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Discussion
(Plate IX)
Marina divaricata is the prototype of a critical group of species endemic to the southern half of Baja California Sur, a group equivalent to Rydberg’s Parosela sect. Divaricatae if P. oculata, misplaced in sect. Diffusae, is substituted for the less closely related P. minor. Johnston considered the group, so far as known up to 1924, as forming collectively a polymorphic entity only varietally distinct from the preceding species, M. parryi, but Wiggins (1940) dissented from this view, accepting Dalea divaricata with a subsp. anthonyi and D. maritima as independent species. Later Gentry (1949) has recognized D. variegata; and to these must be added P. oculata with two very local species described below as Marina catalinae and M. capensis. The differential characters of each member of the group are discussed seriatim under the next following five entries; here I propose only to comment on the separation of M. divaricata sens. str. from M. parryi.
As defined above, M. divaricata can be distinguished from M. parryi by its externally glabrous calyx of characteristically thick texture and by the presence of only 1-3 glands situated above the middle of each recessed fold of the tube. Accompanying this technical character and a significantly different range there are differences in habit and pubescence, D. divaricata being (at least potentially) a taller, more shrubby plant, with shorter, denser racemes, greener foliage, and a glabrous pod. Johnston was misled, I suspect, by the inclusion within his P. divaricata of the gray-pubescent P. maritima, which combines the calyx of genuine M. divaricata with the canescent stems of M. parryi. When M. maritima, with its characteristic aspect, coupled with a specialized habitat on dunes, is segregated, the supposed transition between M. divaricata and M. parryi disappears.
The material of M. divaricata collected in the type region around Magdalena Bay and along the coast southward to the latitude of La Paz is glabrous or nearly so up to the mouth of the calyx and the plants themselves assume the form of low, crooked shrubs often much less than one meter tall. The growth-habit no doubt reflects the environment of exceptionally arid fog-desert. In this same segment of the range the racemes tend to be short and few- flowered, and the calyx-teeth are short, the dorsal one varying from 1.1 to 1.6 mm long (always at least a trifle shorter than the tube). In the Cape region M. divaricata ranges inland along watercourses upward into the oak belt, reaching an elevation of 1800 m in the Sierra de Laguna. Along washes near the coast the plants achieve a stature of 2 m in some places, and become bushy in outline; in the mountains, where they are reported as associated with Quercus devia and Q. idonea in an open woodland community, they may be either similarly erect or diffuse and trailing. Southward, especially along and near the coast, some loose hairs appear on the leaf-stalks, the young twigs, and the dorsal (rarely also the ventral) face of even mature leaflets; and concurrently the dorsal calyx-tooth tends to elongate, reaching a length of 2.1 mm, but varying from 0.5 mm shorter to 0.2 mm longer than the tube. The phase with more or less pubescent foliage combined with relatively long calyx- teeth corresponds with Parosela anthonyi as misinterpreted by Rydberg, whereas that marked by glabrous foliage with long teeth is equivalent to the original D. anthonyi of Brandegee. Wiggins (1940, p. 50) has already remarked on the complete transition between the glabrous northern and the pubescent southern types and noted that they are not even fully segregated geographically. In the circumstances it seems unnecessary to recognize more than one variable entity.
The peculiar range of M. divaricata, with its great altitudinal and edaphic tolerance, is interesting because it embraces (at the same time that it somewhat surpasses) the combined ranges of two closely interrelated species of Dalea, D. benthami and D. trochilina. The former is sympatric with M. divaricata on the fog-desert of the Magdalena region and assumes a similar low, twiggy habit of growth. The latter is sympatric on the Cape sierras with the montane variant of M. divaricata, and like it varies in stature from an erect bush to a trailing subshrub. Obviously these two groups have had a long common history, although the daleas have in the course of time become spatially separated and morphologically discrete, whereas M. divaricata has maintained a continuous fabric of variation through an uninterrupted range.
The lectotypification of Dalea anthonyi requires a word of explanation. To conform with the protologue, the type must be subglabrous up to the orifice of the calyx. I have therefore selected Brandegee’s own specimen as holotype. The paratype cited by Brandegee, Anthony 352, as represented by two sheets retained in the Brandegee collection (UC), has hirsutulous foliage, even though other material distributed under this number is glabrous. Rydberg (1919, p. 54) mistakenly interpreted Parosela anthonyi as the form with thinly pubescent leaves and redescribed the glabrous equivalent as P. variegata.
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Distribution
Mexico North America| Baja California Mexico North America|