A low, sprawling habit is also exhibited by an endemic species of Dalea, one of the finds of the original canoe expedition. Acquainted with the Baskin and Baskin (1984) paper  discussed below, we assumed upon first seeing the Dalea that we had rediscovered a species known only historically from Bibb County, D. gattingeri. A duplicate from our first collection, labeled as Dalea gattingeri, was sent to Robert Kral, who determined it instead to be Petalostemon purpureum (Vent.) Rydb. [= D. purpurea Vent.], a finding we found difficult to accept, based on our experience with the latter species. Once the first author compared Bibb County material with his own collections from elsewhere of D. gattingeri and D. purpurea, he concluded that the Bibb County plant could not be conspecific with either of those taxa. After consultation of the literature, particularly Wemple (1970) and Barneby (1977), it became clear that the Ketona Glade plant differed from any entity previously described. It is morphologically closest, not to any species already mentioned, but to a Texas endemic, D. tenuis (Coult.) Shinners.

Dalea cahaba J. Allison, sp. nov. TYPE: Alabama: Bibb County, ca. 20.5 km NE of Centreville. "County Road 10 Glade," Ketona Dolomite outcrop ca. 2.0 km ENE of the mouth of Four Mile Creek, 1 May 1994, James R. Allison and Timothy E. Stevens 8236 (holotype, NY; isotypes: AUA, DUKE, FSU, GA, GH, JSU, MICH, MO, UNA, US, VDB). Figure 5.

Ab aliis speciebus seriei Purpurearum (Rydb.) Barneby, sectionis Kuhnisterae (Lam.) Barneby, combinatione caulium decumbentium cum spicis fructiferis brevibus (longitudine maxima 2.8 cm), bracteis interfloralibus persistentibus inter calyces et dorsaliter pubescentibus per longitudinem carinae praeter corpus abrupte glabrum (quamquam ciliatum) supra positionem latissimam, et ovariis fructibusque dense pilosulis super saltem dimidium distale distinguenda.

Perennial herb, from a thick (ca. 1 cm), elongate (normally longer than the aerial portion), sparingly branched, dark brown root, in age forking at or just below ground level. Stems usually several, 1.7-6.5 (7) dm long, usually decumbent or weakly ascending, striate-ribbed, pale green, stramineous, or somewhat reddish or purplish, glabrous or distally thinly pilosulous with spreading-ascending or somewhat appressed, weakly curved to sinuous hairs mostly less than 0.3 mm long, either simple or more often branched proximally (or some short, sterile branches also produced above the middle of the stem), the fertile branches monocephalous. Leaves aromatic in life, green, often drying gray-green, petiolate, scarcely bicolored, punctate beneath, rachis and lower (rarely both) surfaces of leaflets thinly strigillose, the hairs on the petiolules more divergent; stipules subulate or the lower lance-acuminate, 1.5-3.5 mm long, primary cauline leaves 1.5-3.7 cm long (including petiole), with broadly margined rachis and 3 or 5 linear or rarely linear-oblanceolate, acute, flat and marginally inrolled or tightly involute leaflets that are 0.5-2.0 cm long, the terminal one slightly the longest, on petiolules 0.5-0.8 mm long, the leaves of axillary spurs shorter, with much smaller, otherwise similar leaflets. Inflorescence a spike on a peduncle (1.5) 2-8.5 cm long (rarely a single flower borne a few mm below the rest), dense in bud, loosening only slightly during and after anthesis, globose to somewhat conelike, becoming oblong-cylindroid or subglobose, without petals (7) 9-12 mm in diameter, the densely pilosulous axis 0.5-2.2 (2.8) cm long; bracts disjointing only with the fruiting calyx, caudate, dimorphic, the lowest 4-7 mm long, the body obovate or lance-obovate, the curving, subulate tail accounting for half or more of the total length, glabrous or pilosulous, the inner ones oblanceolate, 3.5-5 mm long, the tail accounting for about half of the total length, densely tomentulose along the keel and margins, at about the middle of the body the pubescent area extending toward the margins, distally glabrous (except for cilia) beginning 0.5-0.75 mm below the tail; calyx 4-5 mm long, 10-ribbed, densely and very shortly tomentulose, the hairs sinuous, interwoven, oriented in different directions on the same calyx, up to 0.35 mm long or the proximal a little longer, calyx tube subsymmetrically obovoid, 2.5 mm long, not recessed behind banner, glandless, the teeth subdimorphic, the 3 dorsal ones lance-acuminate, (1.7) 2-2.5 mm long, the ventral pair lance-ovate- to ovate-acuminate, (1) 1.4-2 mm long; petals rose-purple, eglandular; banner 3.5-5.3 mm long, the claw 1.5-2.8 mm, the ovate blade 2.0-2.5 mm long, 1.7-1.8 mm wide, hooded at the broadly rounded to slightly emarginate apex, broadly cuneate to broadly and shallowly cordate at the base; epistemonous petals 3.5-4.4 mm long, the blades oblong or oblong-lanceolate, 2.5-3.0 mm long, 1.1-1.8 mm wide, broadly rounded to rounded-truncate at apex, base broadly cuneate, claw 1.0-1.4 mm long; androecium 6-7 mm long, the column 2.2-2.6 mm long, the filaments free for 4-4.5 mm, the connective gland-tipped, the yellow or orangish anthers (0.7) 0.9-1.2 mm long. Fruit a pod, obliquely semi-obovoid in profile, 3.2-4.4 mm long, including the persistent style; the ventral suture nearly straight, the dorsal convexly arched, the style- base eccentrically terminal, the valves in proximal third hyaline and glabrous, distal two-thirds thinly papery, tomentulose; seed brown or olivaceous, 1.9-2.2 (2.4) mm long, (1.2) 1.5-1.7 mm wide at the middle. Chromosome number unknown.

Flowering May-June; fruiting June-September.

English Name: Cahaba Prairie-clover.

Paratypes. Alabama: Bibb Co., (topotype), 2 May 1998, A. 10649 (AUA, BRIT, DUKE, FLAS, FSU, IBE, JSU, TAMU, UNA, US, USCH); "Pratts Ferry. Aug.," H.[?] J. Smith s.n. (UNA); 11.9 km NNE of Centreville, "Pratt Glade West," 19 Jul 1992, A. and S. 6876 (AUA, GA, JSU, UNA); 12.2 km NNE of Centreville, "Westside Glade West," 14 Jun 1993, A. and S. 7753 (GA, NY, UNA, US); 14.7 km NE of Centreville, "Brown's Dam South Glade III," 28 May 1994, A. et al. 8338 (AUA, GA, MO, NY, UNA, US, VDB); 14.8 km NE of Centreville, "Riverbend Glade," 13 Jun 1993, A. and S. 7718 (AUA, JSU, UNA);15.3 km NE of Centreville, "Desmond's Glade," 7 Jun 1998, A. 10900 (MO, NY, TENN, US).

Dalea cahaba is present on all of the larger glades but is absent from the smaller ones found near the western periphery of the glade region. Like Coreopsis grandiflora var. inclinata, it is a true heliophyte, flowering only in exposed situations.

As cited among the paratypes, at least one historical collection of Dalea cahaba exists. Baskin and Baskin (1984) refer to three previously unannotated 19th Century Alabama collections at the University of Alabama (UNA), labeled by their collectors as Kuhnistera gattingeri Heller. The Baskins found them all to be Petalostemon gattingeri (Heller) Heller [this and the preceding =Dalea gattingeri], determinations concurred with by the late Duane Isely. Smith's Bibb County collection is, in fact, D. cahaba.⁽⁵⁾

Aside from the strongly diagnostic transverse band of pubescence on the otherwise glabrous or glabrescent bodies of the interfloral bracts, Dalea purpurea is very different in aspect from the other three taxa discussed here, since it is commonly an erect or strongly ascending plant with polycephalous stems [branched above the middle, each branch terminating in a spike, as figured in Barneby (1977) and Isely (1990)]. A wide-ranging species, its populations geographically closest to Bibb County are on chalk glades [Mohr's (1901) "bald prairies," as at Gallion] of the Black Belt region of the Gulf Coastal Plain of Alabama and Mississippi, where it is a common plant. Conversely, D. cahaba, D. gattingeri, and D. tenuis have a decumbent to weakly ascending habit combined with stems ordinarily branched only below the middle. Rare, decumbent forms of D. purpurea have been reported (Wemple 1970, Barneby 1977), nevertheless referable to that species on the basis of bract pubescence and branching pattern.

Dalea gattingeri is a plant of limestone glades of higher latitudes than Bibb County, with its nearest known localities more than 135 km to the north, in Morgan County, Alabama (Kral 1983). It differs markedly from D. cahaba and D. tenuis by its longer, often sinuous spikes (mostly more than 2.5 cm long, reaching as much as 7.5 cm), which loosen during and after anthesis, partially exposing the axis (at least in pressing) and accompanied by the loss of most of the interfloral bracts. Though its spikes are long, its peduncles are short, only 0-3 cm long, while those of D. cahaba and D. tenuis are seldom less than 3  cm long. The antrorse calyx pubescence of D. gattingeri resembles somewhat that of D. purpurea, but its interfloral bract pubescence pattern is more like that of D. cahaba and D. tenuis, except that the tail is pubescent or at least distinctly ciliate, rather than essentially glabrous. Furthermore, D. gattingeri often has 7 or sometimes even 9 leaflets, as shown in its photograph in Duncan and Duncan (1999), rather than the maximum of 5 found in D. cahaba and D. tenuis.

Dalea tenuis shares with D. cahaba a decumbent habit, permanently dense and conelike spikes mostly less than 2.5 cm long [Barneby 1977, though Wemple (1970) gives the length to 4.4 cm], and a similar pattern of bract pubescence. Morphologically, D. tenuis stands apart from the three other species here discussed by the distinctly retrorse pubescence of the calyx tube, the almost totally glabrous ovary (pilosulous only at the style-base), and by its long peduncles (as much as 15 cm long, vs. a maximum of 8.5 cm in D. cahaba). Dalea cahaba has ovaries and pods that are densely tomentulose on at least the distal two-thirds and a distinctive calyx pubescence, the hairs more appressed than in its relatives, and peculiar in varying from antrorse to retrorse in orientation on the same calyx, sinuous and interwoven, the result a comparatively disheveled calyx vestiture. A further difference is found in the calyx teeth, which are often about as pubescent as the calyx body in D. cahaba, usually glabrous or thinly pilosulous (though ciliate) in D. tenuis.

A genetic comparison of Dalea cahaba and related species would be desirable, to assess whether the morphological similarities to the Texas endemic (D. tenuis) reflect common descent (indicated by greater genetic similarity to D. tenuis) or convergence (greater similarity to D. gattingeri).