Sabulina diffusa M. Brock, 2023

Sabulina diffusa M. Brock View in CoL , sp. nov. ( Fig. 4 View FIG ). TYPE: U.S.A. KENTUCKY. Woodford Co.: Limestone ledge, Mundy’s Landing , 25 May 1955, M. Wharton 8914 (HOLOTYPE: GH; ISOTYPES: APSC, NCU) .

Diagnosis.— Sabulina diffusa appears morphologically similar to S. michauxii , S. muscorum and S. patula but differs as follows: from S. michauxii in its reduced to absent axillary leaves and its stipitate-glandular inflorescence branches;from S. muscorum in its narrower and more linear leaves, its tuberculate seed surface (as opposed to pebbled-papillose) and more diffuse-divaricate mature inflorescence branches;and from S patula in its larger seeds, its tendency to have fewer and weaker sepal nerves ( Figs.5 View FIG , 6 View FIG ), its diffuse-divaricate mature inflorescence branches ( Fig.4 View FIG ), and its shorter and less acuminate sepal tips ( Figs. 5 View FIG , 6 View FIG ). In addition, S. diffusa has a later flowering time where sympatric with S. patula .

Description.— Taprooted annual. Stems ascending to lax, 10–27 cm, stipitate-glandular, sometimes minutely so. Leaves linear, up to 25 mm × 1 mm, decreasing in size distally, 1-veined abaxially (weakly 3 veined at base), linear, glabrous to stipitate-glandular; reduced axillary present or absent. Inflorescences spreading-ascending in flower, becoming diffusely divaricate-branching in fruit; bracts 1-nerved. Pedicels 1–3 cm, stipitate-glandular. Sepals lanceolate, 3.5–5.2 mm, apex acute (rarely acuminate), glabrous to sparsely stipitate-glandular; green with hyaline margin, prominently 3 veined (occasionally 5), spaces between veins wider than veins; petals 5–8 mm long, weakly notched. Seeds reddish brown to black, 0.5–0.7(0.75) mm across, tuberculate with low, rounded ridges.

Additional collections. GEORGIA. Murray Co.: cedar glade at cross road between old and new GA 411 , opposite and W of Carters regulation dam, 0.5 mi W of L&N, Conasuga ribbon dolomite, 10 May 1986, Samuel B . Jones 24784 ( GA). KENTUCKY. Barren Co.: Prewitt’s Knob , 0.5 mi SW of Cave City on US 31 W , 28 Apr 1979, G. P . Johnson 611 ( APSC). Edmonson Co.: vicinity of Mammoth Cave , May 1899, E. J . Palmer s.n. ( NY). Estill Co.: Grassy Knob , cedar glade like area near the summit on SW corner of knob, ca. 2 air mi SW of Hargett, 11 Jun 1983 M . Medley 8142 ( APSC). Garrard Co.: narrow limestone point between unnamed stream and Dix River near end of Bryantsville- Buena Vista Road , 8 May 1987, M . Medley 16005 ( APSC). Jackson Co.: Berea College Forest, Owsley Fork Reservoir west-trending Mississippian limestone outcrop cliff crevices and ledges, 26 May 1983, R. L . Thompson 83-1244 ( APSC, BEREA). Jessamine Co.: Brooklyn Bridge on US 68 at Kentucky River , wooded bluffs just east of bridge, 1 Jun 1984, M . Medley 10246 ( APSC). Madison Co.: Berea College Forest , on limestone cap on NW and N lobes of Robe Mountain , 14 Jul 1982, D. Taylor 1819 ( BEREA, LSU). Mercer Co.: Shaker Ferry on W side of ephemeral stream ravine, dry limestone bluff edges and upper bluffs, 1 Jun 1987, M . Medley 10188 ( APSC). Pulaski Co.: by Short Creek on Short Creek Road near Stab , 20 May 1983, M . Medley 7733 ( APSC). Warren Co.: Hwy 31 W glade, 4 Jun 1971, Baskin 1053 ( APSC). MISSOURI. Howell Co.: in section 3, 4 mi E of Lanton limestone glade along Myatt Creek , 27 Apr 1938, J . Steyermark 5174 ( MO). Oregon Co.: The Narrows, W of Calm limestone glade above Blue Spring , 11 May 1935, J . Steyermark 18911 ( MO). TENNESSEE. Claiborne Co.: Hwy 33 and Sharps Chapel Road, in PLROW , 36°21'3.84”N, 83°44'10.93"W. Abundant on large mossy boulders and on limestone pavement. 19 Apr 2016, Aaron Floden 2917 ( TENN). Knox Co.: on limestone gravel and outcrops, in power line cut near quarry at Marbledale , TN, 35.965206 -84.136571, 16 May 2003, C GoogleMaps . Winder s.n. ( TENN). White Co.: vicinity of Blue Hole at Rock Island , 23 May 2011, D. Estes 11956 ( APSC). VIRGINIA. Lee Co. : cedar-limestone barrens west of county road 656, 0.6 mi S of US 58 , 6 mi west of Jonesville , 7 Jun 1984, L. J . Uttal 13194 ( CM, FSU) .