Dalea carnea
Rupert C. Barneby
43. Dalea carnea (Michaux) Poiret
(Plate LVII)
Herbs, when adult sometimes suffrutescent at base, 3-8 (10) dm tall, glabrous except for minutely ciliolate bracts and internally tomentulose calyx-teeth, variable in habit of growth, the stems either relatively stout and erect or ascending in clumps, then virgate and paniculately branching distally, or bushy-branched from middle or near base, or diffuse to decumbent or truly prostrate, monocephalous only when depauperate, in any case either green or purple-castaneous, striate-ribbed, glandless or minutely remotely gland-sprinkled distally, the foliage green, the leaflets somewhat bicolored, smooth above, punctate and often brownish-green beneath; leaf-spurs 0.6-1.5 mm long; stipules subulate, linear-lanceolate, or setiform, becoming dry and fragile, 1-4.5 mm long; intrapetiolular glands minute or 0; post-petiolular glands immersed or if prominulous small; leaves subsessile or shortly petioled, the primary cauline ones 1.5-3.5 cm long, with narrowly margined, usually punctate rachis and 5-9 elliptic or oblanceolate, acute or if obtuse then gland-mucronate, or abruptly short-acuminate, either flat but marginally elevated or more often boat-shaped, incurved, dorsally keeled leaflets up to (5) 6 -17 mm long, the largest at least 1 mm wide when expanded (or 0.5 mm as seen in profile), the very short-stalked or subsessile terminal one not or scarcely longer than the last pair; peduncles 0 or nearly so, but some distal leaves commonly reduced to a stipuliform bract and the stem then naked under the spike for 2-8 (13) cm; spikes very dense, conelike, the mature calyces mostly horizontal to the axis, the lowest declined, without petals ovoid-oblong becoming oblong-cylindroid or subglobose, 7-10 mm diam, up to 5-30 mm long, the first of each main stem commonly longer than those of lateral branchlets; bracts deciduous only with the fruit, subhomomorphic or the lowest firmer, longer and more persistent than the rest, lanceolate or lance-acuminate, (2) 2.5-5.5 mm long, ± 1 mm shorter to 1 mm longer than the subtended calyx, purplish or brownish except at very base, often charged dorsally with a few tiny glands; calyx subtended by bracteolar spicules 0.6-1.5 mm long, 2.7-4.3 mm long, bluntly angled but not or inconspicuously ribbed, the rather narrowly campanulate tube 2-3.2 mm long, often a trifle constricted near orifice, this deeply recessed behind banner, the intervals between the immersed castaneous ribs heavily castaneous-flecked glandless or charged distally with 1-3 small colorless glands, the teeth of nearly equal length, 0.6-1.5 mm long and as long as tube, all subulate or the ventral pair ovate-subulate, all densely but minutely pilosulous internally, externally livid or greenish-livid in contrast to the (dry) pinkish-brown tube; petals white, flesh-pink, or rose-lilac, glandless or the banner exceptionally charged at base of blade with 2 minute glands; banner 3.8-5.7 mm long, the blade and claw of ± equal length, the former scoop-shaped, i. e. ovate, broadly cuneate at base, entire or emarginate at the strongly hooded apex; epistemonous petals 2.3-4.5 mm long, the blades oblong, oblanceolate, or oblong-elliptic, either abruptly truncate or cuneately tapering at base, the claw varying from ½ as to nearly as long; androecium 5-9.5 mm long, the column 1.7-4 mm, the free filaments up to (2.2) 2.5-6 mm long, the connective gland-tipped, the pallid anthers 0.6-0.85 mm long; pod 2.5-3 mm long, obliquely clavate-obovate in profile, strongly incurved, the ventral suture short and thick, the dorsal one very strongly convex, the prow heavily thickened and prominent (0.25-0.4 mm thick), the style-base subterminal or appearing lateral, the valves thinly papery (scarcely hyaline) at base, from middle livid, wrinkled, ± glandular, commonly pilosulous at apex like the style, sometimes glabrous.
A complex, polymorphic species of wide dispersal on the Gulf and Atlantic Coastal plains from extreme southeastern Louisiana to Georgia and south to the Everglades, related to the allopatric (more northern and western) D. Candida, but differing in the almost terete (not pleated) calyx asymmetrically cleft behind the banner and in the shape of the little scoop-shaped, not heart-shaped banner-blade. The more nearly related and sympatric D. feayi of peninsular Florida is distinguished from pink-flowered D. carnea var. carnea by its extremely narrow leaflets combined with few-flowered globular spikes. The only other prairie-clover present in the range of D. carnea is D. pinnata, entirely different in its long-toothed plumose calyces compressed into a head subtended by several whorls of purple-brown bracts.
My concept of D. carnea sens lat. coincides with Petalostemon carneum, albidum, and gracile of Wemple’s revision (1970, pp. 31-36); most of the material that I have seen was studied also by Wemple and we have no substantial disagreement as to the scope of the three entities, only as to their nature and taxonomic rank. My interpretation of the material is that it represents a virtually continuous series of variants which have developed marked morphological differences toward three extremities of a continuous range, these differences apparently encouraged by adaptation to selective microhabitats. Wemple develops the theory that there are two older species, P. carneum of peninsular Florida and P. gracile of the Gulf Coast prairie, both native in undisturbed lowlands moist in the wet summer season, and P. albidum which arose through hybridization between the primary species and, adapting to a drier regime in the disturbed woodlands of interior northern Florida, has thence moved northward as an autonomous entity into Georgia. Continuing studies by Wemple may well substantiate this hypothesis but for the present the views expressed here seem equally rational. The extreme forms of D. carnea are readily recognized: at one end typical var. carnea, with mostly erect, coarse, erect but either virgate or bushy-branched stems densely leafy with spurs in all primary axils, and oblong to cylindric spikes of relatively large pink flowers; at the other end var. gracilis, with flexuously procumbent, very slender, sparsely and remotely leafy stems mostly lacking axillary short- shoots, and with shortly oblong to subglobose spikes of small white flowers. These are fully allopatric, so far as known, but almost converge near the lower Suwanee River in northern Florida. Difficulty arises only with var. albida, dispersed across northern Florida, north into Georgia, and overlapping to some degree the ranges of the other two. In habit var. albida varies from erect to diffuse and from moderately robust to almost the equal of var. gracilis for slenderness; and its heads of white flowers are intermediate in overall size and in dimensions of the parts. The inner petals of var. gracilis and var. albida tend to have claws relatively longer than those of var. carnea, but this is a variable feature, and it cannot be over-emphasized that there is no structural difference in the flowers.
References: [Article] 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.Multimedia:
