An Erigeron L. that appeared to be a variant of the widespread and often weedy Erigeron strigosus proved to be one of the most characteristic plants of the Ketona Glades, absent only from one of the smallest outcrops, near the western periphery of the glade region. The distinctiveness of the Ketona Glade plant was apparent right away, due to the clumps of erect or strongly ascending and unusually narrow leaves found around the bases of most of the flowering stems. When we removed plants from the substrate, it was clear that most of the basal rosettes were terminal to short rhizomes.

Erigeron strigosus Muhl. ex Willd. var. dolomiticola J. Allison, var. nov. TYPE: Alabama: Bibb County, ca. 12.4 km NNE of Centreville. "Westside East Glade,"  Ketona Dolomite outcrop ca. 0.4 km W of the mouth of Pratt Creek, 10 Jun 2000, James R. Allison 12396 (holotype, NY; isotypes: AUA, BRIT, DUKE, FLAS, FSU, GA, GH, IBE, JSU, MICH, MO, NCU, TAMU, TENN, UARK, UNA, US, USCH, VDB). Figures 6 and 7. 

Ab varietatibus descriptis E. strigosi Muhl. ex Willd. duratione vulgo perenni, et foliis, etiam radicalibus, linearibus vel linearibus-oblanceolatis et plerumque minus quam 3.5 mm latis differt.

Perennial herb, with short rhizomes that bear tufts of overwintering leaves at the upturned ends, mostly (3.4) 5.5-8.0 (8.9) dm tall. Stems (1-) several (-9), usually  maroon at the base, upwards maroon or more often green, becoming brown with age, several- (usually pale-) ribbed, with strigillose or weakly ascending short hairs, the hairs sparse low on the stem, becoming moderately dense in the inflorescence and often very dense below the heads. Leaves ciliate and very sparsely to moderately strigillose, firm, the basal erect or ascending, becoming nearly prostrate  after frost, linear, tapering to indistinct petioles that are usually purplish proximally, at least in youth, their blades distally remotely and shallowly few-toothed or entire, (2.5) 4.0-15.5 cm long (including petiole) and 1-3.5 (6) mm wide, the cauline leaves well spaced  (internodes mostly more than 2 cm long), linear-oblanceolate or more often linear, gradually reduced above, very rarely with an axillary fascicle of a few greatly reduced ones, entire or the lower remotely and shallowly few-toothed. Inflorescence a diffuse panicle of several to numerous heads; peduncles sparsely bracteate, the bracts linear and mostly less than 2 cm long; involucre 2.8-3.0 (4) mm high, phyllaries unequal, the outer  shorter (1.1-1.5 mm long vs. 2-2.3 mm), acute or short-acuminate, sparsely strigillose, with brown midrib and light greenish or yellowish margins that are distally minutely glandular-erose; ligules numerous, white, occasionally tinged with lavender, 0.6-0.9 mm wide, mostly 4-6 (7) mm long; disk 5.4-6.0 mm broad, the disk-corollas 1.1-1.7 mm long, the lobes about 0.2 mm long. Pappus double, the outer setose-squamellate, the inner of very fragile bristles, the bristles lacking in the pistillate  (ray) flowers. Fruit a hairy, 2-nerved achene, 0.8 mm long. Chromosome number unknown.

Flowering late May until frost, fruiting June-frost.

English Name: Cahaba Daisy Fleabane.

Paratypes. Alabama: Bibb Co., 6 miles N of Centreville/Brent, Hwy. 5, Ketona Dolomite glade, 7 Jun 1996, John R. MacDonald 9532 (VDB); 8.9 km NNW of Centreville, "Highway 219 Glade," 25 Jun  1998, A. 11020 (GA, GH, MICH, MO); 10.0 km NNE of Centreville, "Schultz Creek Church Glade East," 4 Sep 1993, A. and S. 7947 (GA, UNA); 12 km  NNE of Centreville, "Lady-tresses Glade South," 23 May 1999, A. 11922 (AUA, JSU, UNA); 17.3 km NE of Centreville, "Enchanted Glade," J. Allison and M. Moffett 11321 (AUA, JSU, UNA, VDB); 17.8 km NE of Centreville, "Alligator Glade," 19 Aug 2000, A. 12501 (AUA, DUKE, GA, GH, JSU, MICH, MO, NCU, NY, UNA, US); 20.5 km NE of Centreville, "County Road 10 Glade," 24 May 1999, A. 11935 (AUA, GA, JSU, NY, UNA).

Erigeron strigosus var. dolomiticola usually occurs as scattered individuals or small groupings, in full sun or at glade margins where it receives full sunlight part of the day. Occasionally it grows more densely and can be an aspect dominant in late spring and summer

The Ketona Glade endemic seemed clearly aligned with Erigeron strigosus and E. annuus (L.) Pers. in having disk flowers with a double pappus, with an outer series of setose scales and inner series of capillary bristles, and with ray flowers bearing only the scales. The tufts of remarkably narrow radical leaves seemed distinctive, approached in slenderness only by the very narrowest-leaved extremes of E. strigosus Muhl. ex Willd. var. beyrichii (Fisch. & C. A. Mey.) Torr. & Gray ex Gray, as found in xeric habitats such as sand ridges (e.g., A. 11852, GA, NCU, NY). Unlike those of the latter, rosettes of the Ketona Glade plants were terminal to rhizomes, which seemed a clear indication of perennial duration (also evidenced by the occasional persistence of dried stalks of flowering stems from the previous year). The persistence of these rosettes into fall and then winter (when they became lax) was final proof that the plant was  perennial and therefore unlike described varieties of E. strigosus, which are considered annual or biennial (Cronquist 1947, USDA 2000). As no significant difference was found in the flowers of the Ketona Glade endemic from those of var. beyrichii, the decision was  to describe this entity as a new variety, using the rank best conforming with the currently accepted infraspecific taxonomy of E. strigosus.

Late in October of 1992, Allison traveled to Middle Tennessee to visit the herbarium at Vanderbilt University, confer with Robert Kral, and make collections from cedar glades of Onosmodium molle ssp. molle and especially Dalea gattingeri, for comparison with their Bibb County congeners. Growing on virtually every glade visited were populations of Erigeron strigosus, like var. dolomiticola of manifestly perennial duration: green, healthy-looking and obviously overwintering rosettes were connected by rhizomes to flowering stems that were clearly senescing, though many still with some flower-heads (Figure 7). These rosette leaves were consistently wider than those of var. dolomiticola, though not achieving the maximum width seen in the rosettes of the (annual) varieties strigosus and beyrichii. These cedar glade populations also had leaves, stems, and involucres more sparsely pubescent than is usual in other varieties.

 Subsequently, we found additional perennial Erigeron strigosus populations, virtually glabrous like those on Middle Tennessee cedar glades, on and near many limestone glades in northern Alabama and on a single glade in northwestern Georgia. Surprisingly, we found no populations on any of the multiple glades visited in Catoosa County, Georgia, where glades are the most numerous in that state and the characteristic cedar glade flora is well developed. The plant was also absent from glades in Bullitt County, Kentucky, visited by Allison. It should be sought on other glades in that state.

As these sparsely strigillose, broad-leaved populations are of perennial duration, have been found only in a particular habitat (shallow soil over limestone), and have a much more restricted range, they should not be considered typical Erigeron strigosus var. strigosus (nor the weakly differentiated var. beyrichii). As they have consistently wider rosette leaves, are endemic to a different type of rock outcrop, and are allopatric with the narrow-leaved perennials corresponding to var. dolomiticola, neither should they be referred to the Ketona Glade taxon. Therefore, they are described here as a new variety, E. strigosus var. calcicola.

Erigeron strigosus Muhl. ex Willd. var. calcicola J. Allison, var. nov. TYPE: Tennessee: Rutherford Co., ca. 18.7 km E of Murfreesboro, ca. 3.7 km NNW of  Readyville; limestone glade west of Tassey Rd., ca. 0.2 rd. km N of crossing of Andrews Creek, 22 Jul 2000, James R. Allison 12431 (holotype, NY; isotypes: DUKE, GA, GH, MO, NCU, TENN, UNA, US, VDB). Figure 7.

Planta perennis ut in varietate dolomiticola J. Allison sed ad saxum calcareum crescens, et foliis radicalibus perspicue laterioribus (plerumque plus quam 3.8 mm latis) ab illa varietate distinguenda.

Similar to the annual (or sometimes biennial) var. strigosus but (1) less pubescent (mid-cauline leaves glabrous, except for cilia and often some well spaced, strigillose hairs on the midvein, the rosette leaves sometimes sparsely strigillose); (2) a perennial (given normal precipitation) with overwintering basal rosettes; with (3) a more restricted range (northern Alabama to northwestern Georgia and central Tennessee) and (4) a restricted habitat (endemic to limestone outcrops). In addition to the often slightly larger involucres and usually less diffuse and more conspicuously bracteate inflorescence that cause it to resemble var. strigosus, it differs from the perennial var. dolomiticola by having wider, more sparsely strigillose leaves, with those of the rosettes (3.2) 3.8-15 (21) mm wide, and in growing only over limestone, rather than dolomite.

Flowering (late April) May-frost, fruiting late May-frost.

English Name: Limestone Daisy Fleabane.

Paratypes. Alabama: Colbert Co., 14.8 km SSE of Tuscumbia. Littleville, jct. Lynwood Ave. and Durward Dr., 19 Aug 2000, A. 12513 (UNA). Franklin Co., Isbell, limestone barrens, 27 May 1972, R. Kral 46739 (MO, VDB). Jefferson Co., 13.5 km NE of Birmingham, Murphree Rd., Ketona, 5 Oct 1993, A. and S. 8026 (UNA). Lawrence Co., 17.8 km WNW of Moulton, Co. Rd. 39, formerly Co. Rd. 7, 25 May 1999, A. 11948 (AUA, UNA, US, VDB). Madison Co., 6.8 km SE of Huntsville, lower slope of Monte Sano, 20 Aug 2000, A. 12516 (JSU, NCU, UNA). Morgan Co., 6.3 km WSW of Falkville, State Crusher Rd., 23 May 2000, A. 12444 (AUA, DUKE, FLAS, FSU, GA, GH, JSU, MICH, MO, NCU, NY, UNA, US, USCH, VDB). Georgia: Floyd Co., 12.4 km SW of Rome, Cunningham Rd., 4 May 1999, J. Allison and R. Ware 11859 (GA, GH, MO, NCU, NY, US). Tennessee: Bedford Co., 6.3 km ESE of Shelbyville, US Hwy. 41A, 22 Jul 2000, A. 12438 (FSU, GH, MICH, NY, TENN, US, USCH, VDB). Cannon Co., 8.7 km WNW of Woodbury, Tassey Rd., 22 Jul 2000, A. 12429 (NY, TENN, VDB). Davidson Co., 20.0 km SE of Nashville, Tenn. Hwy. 171, 12 Oct 2000, A. 12591 (TENN, VDB). Giles Co., 6.7 km SSW of Pulaski, Donahue Rd., 12 Oct 2000, A. 12587 (AUA, BRIT, DUKE, FLAS, FSU, GA, GH, MICH, MO, NCU, NY, TAMU, TENN, US, USCH, VDB). Marshall Co., 17.4 km N of Lewisburg, Tenn. Hwy. 99, 22 Jul 2000, A. 12439 (GA, NCU, TENN, VDB). Maury Co., 19.0 km NE of Columbia, US Hwy. 431, 22 Jul 2000, A. 12440 (NY, TENN, US, VDB). Williamson Co., 17.4 km SSE of Franklin, Tenn. Hwy. 247 and I-65, 22 Jul 2000, A. 12441 (TENN, VDB). Wilson Co., 19.8 km SSW of Lebanon, Fall Creek Rd., 22 Jul 2000, A. 12434 (MICH, NY, UNA, US, TENN, VDB).

As an aid in understanding the differences among southeastern varieties of Erigeron strigosus, Cronquist's (1980) key may be brought up to  date by the following modifications:

1. Plants annual or rarely biennial, of various, often ruderal habitats.

2. Heads tiny, the involucres only 2-3 mm high; inflorescence diffuse and subnaked, the peduncles often flexuous; coastal states, chiefly on Coastal Plain, from New Jersey to Florida and Texas ... var. beyrichii.

2. Heads averaging larger, the involucre (2.5) 3-4 mm high; inflorescence not diffuse, or if so, then somewhat leafy; widespread, but seldom on Coastal Plain south of Virginia ... var. strigosus.

1. Plants normally perennial (sometimes killed prematurely by severe drought), of shallow soil over calcareous rock.

2. Rosette leaves linear-oblanceolate, less than 3.5 mm wide; cauline leaves sparsely to moderately strigillose; growing over dolomite in Bibb County, Alabama ... var. dolomiticola.

2. Rosette leaves oblanceolate to narrowly obovate or spatulate, more than 3.8 mm wide; cauline leaves glabrous (but ciliate) except along the midvein; growing over limestone in northern Alabama, northwestern Georgia, and Middle Tennessee ... var. calcicola.

Morphologically transitional to Erigeron annuus (Cronquist 1947, 1991) is a fifth variety, var. septentrionalis (Fern. & Wieg.) Fern. It can readily be distinguished from the other four varieties by its longer, spreading stem pubescence and by the longer, more distinctly flattened hairs of its involucre, characters it shares with E. annuus. Although not mentioned by Cronquist (1980) in his treatment of Asteraceae of the Southeast, var. septentrionalis reportedly ranges from Tennessee and Arkansas northward and westward (USDA 2000).

In the perennial varieties, calcicola and dolomiticola, as long as soil moisture levels are adequate, offsets are produced throughout the growing season by means of short, slender horizontal rhizomes that become upturned and produce secondary rosettes.⁽⁶⁾ If soil moisture and temperature conditions (and perhaps day length?) continue to be favorable, these rosettes bolt into flowering stems and additional offsets are produced. Those rosettes that have been produced but have not yet bolted by the end of autumn persist through the winter and bolt the following spring, as do additional offsets produced during the winter months.

The shallow soils in which the newly described perennial varieties grow are susceptible to desiccation during occasional summer droughts. Though these varieties are rather drought tolerant, under very low levels of soil moisture rosette development is suppressed or greatly reduced. Mortality is sometimes quite high (e.g., during the severe droughts of 1999 and 2000), but even in summers of normal rainfall, we observed some flowering plants that lacked secondary rosette development. If all their rosettes have withered, such plants presumably will not overwinter. Probably these were plants whose microhabitats had become unfavorable for continued growth or were older plants that had exhausted their capacity for rosette proliferation. It would be interesting and informative to track the development of individually marked or mapped plants over several years.

Erigeron strigosus var. dolomiticola seems never to stray from its Ketona Glade  habitat, exhibiting none of the weediness so characteristic of the annual varieties. Variety calcicola, however, can often be found on road shoulders or lawns in the vicinity of cedar glades, provided limestone is close to the surface. In such places the early successional conditions of the glade habitat are maintained or simulated by occasional mowing, a practice well tolerated by variety calcicola (which responds by flowering at a lower height)  and by some of its weedier glade associates, such as Croton monanthogynus Michx. and Verbena simplex. During the prolonged drought of 2000 over the cedar glade country of northern Alabama and Middle Tennessee, such ruderal sites often yielded better specimens than the populations on the (desiccated) glades nearby, such as the paratype collection from Cannon County,  Tennessee. Care must be taken in the identification of plants collected from such places as well as from disturbed areas on genuine cedar glades (such as where roads have encroached upon glade habitat). Variety strigosus is sometimes associated with var. calcicola under these conditions, and so it is very helpful that material of var. calcicola, even when lacking rosettes, is still readily distinguishable by the essentially glabrous cauline leaves. However, some plants intermediate between var. calcicola and strigosus in leaf width and in density of pubescence have been found in roadside glade habitats, suggesting probable introgression (e.g., A. 12500b, GA).

Erigeron strigosus was considered by Cronquist (1947) to be predominantly apomictic. Thus it might be expected to produce distinctive, relatively uniform races that appear to "breed" true but are essentially asexual. Certainly one should be cautious in describing new taxa within a group known to include apomicts. However, infraspecific taxa are currently recognized in the taxonomy of E. strigosus (e.g., USDA 2000). In this case there is a demonstrable difference in duration in varieties dolomiticola of dolomite glades and calcicola of limestone glades from that of previously described varieties of E. strigosus. This is correlated with particular habitats, habitats that surely have selected for physiological adaptations that are phenotypically invisible but undoubtedly present. This suggests more than a trivial genetic difference in the perennial glade endemics from the currently accepted varieties of E. strigosus.

Since Cronquist's (1947) monograph of the genus Erigeron north of Mexico, diploid, sexual populations of E. strigosus have been reported (Turner and Flyr 1966, Nesom 1978). The ploidy and breeding systems of the two new perennial varieties are unknown, but the annual duration of previously named varieties of E. strigosus is considered an advanced trait within the genus (Cronquist 1947). The discovery of perennial varieties raises the question of whether they represent "primitive," relictual forms of the species or are, instead, the result of a reversal of an existing (annual) condition as an adaptation to a new environment. If the perennial duration is primitive, the diploid condition should be correlated with it, as it is with a sexual breeding system rather than with apomixis (Nesom 1978). Neither of the papers reporting diploid counts was focused on E. strigosus, and they contained no infraspecific determinations for chromosome counts of that species (though vouchers were cited for all, so such determinations are feasible). They also did not discuss any correlation in E. strigosus of ploidy level with duration or morphology. In short, many unanswered questions remain about variation in the strigosus complex. Certainly a determination is needed of the ploidy level(s) of varieties dolomiticola and calcicola, as well as a careful assessment of the duration of the various diploid and polyploid cytotypes of E. strigosus.