Baccharoides Moench, 1794

Robinson, Harold, Skvarla, John J. & Funk, Vicki A., 2016, Vernonieae (Asteraceae) of southern Africa: A generic disposition of the species and a study of their pollen, PhytoKeys 60, pp. 49-126 : 55

Baccharoides Moench, 1794 Figures 1 A, B ; 2 A ; 3 A–I

Baccharoides Moench, Methodus 328 (1794). - Type: Conyza anthelmintica L.

Ascaricida Cass., Dict. Sci. Nat. 3, suppl. 38 (1817), nom. superfl. - Type: Conyza anthelmintica L.

Candidea Tenore, Atti Reale Accad. Sci. Sez. Soc. Reale Borbon 4 (CI. Botan.): 104, t. 1, 2 (1839). - Type: Candidea senegalensis Tenore.

Vernonia subsect. Stengelia Sch. Bip. ex Walp., Repert. Bot. Syst. 2: 946 (1843). - Type: Vernonia adoensis Sch. Bip. ex Walp.

Stengelia Steetz in Peters, Reise Mossamb., Bot. 360. 1864. - Type: Vernonia schimperi DC.

Vernonia sect. Stengelia (Sch. Bip. ex Walp.) Benth. in Benth. & Hook.f., Gen. Pl. 2: 127 (1873).

Resources.

Treatment by Isawumi et al. (1996).

Descriptions.

Annual or perennial herbs, suffruticose; stems erect or reclining; hairs short-stalked with an erect, elongate apical cell. Leaves alternate, narrowly petiolate; blades chartaceous, ovate to elliptic, serrate, secondary veins pinnate, ascending at 45° angles or more. Inflorescence with single lateral or terminal head or heads in corymbiform groups; peduncles usually solid, sometimes fistulose. Heads with involucres broadly campanulate or hemispherical; bracts 25-100 in 4-8 series, mostly gradate but with outer bracts sometimes elongate and foliiform, tips of bracts appendaged, white or colored; receptacles epaleate. Florets 25-100 in a head; corollas reddish or lavender to white, with long slender basal tube, limb abruptly expanded at base, cylindrical, with lobes about as long as throat, erect, with various hairs and glands outside, inside with cells elongate, transversely striate; anther thecae spurred with small tails; endothecial cells with nodular thickenings on tranverse walls; apical appendages oblong-ovate, rounded or acute at tips, glabrous; nectary elongate, cylindrical; style base without node; sweeping hairs acicular. Achenes cylindrical or turbinate, 8-20-costate, glabrous or with setulae distinctly cleft or with glands or idioblasts, carpopodium annuliform, large to obsolete, with thickened porose walls, raphids in ovules elongate, with rhomboid tips; pappus pluriseriate, persistent or caducous, inner capillary, flattened, barbellate on margins, sometimes shortly connate at base, sometimes with outer row of small scales. Chromosome number x = 10 ( Jones 1970, Mathew and Mathew 1983)

Pollen. 43.5-72.0 μm diam. ( Isawumi et al. 1996); tricolporate, echinolophate; lacunae regularly disposed, one at each pole, 2 across intercolpus; tectum restricted to muri, with distinct microperforations; stout baculae under muri firmly attached to footlayer (Fig. 3 A–I ).

Most notable secondary metabolites, sesquiterpene elemanolides ( Bohlmann and Jakupovic 1990, as Vernonia anthelmintica (L.) Willd., Vernonia hymenolepis A. Rich., Vernonia lasiopus O. Hoffm.), eudesmanolide ( Bohlmann and Jakupovi 1990, as Vernonia adoensis Sch. Bip. ex Walp.).

Figures

Figure 1. Photographs of Baccharoides, Bothriocline, and Vernonia potamophila. Baccharoides adoensis (Sch. Bip. ex Walp.) H. Rob. A Habit B Close up of flowering head: note that the corollas are narrowed near the apex and have an lengthened throat that is much longer than the short lobes and the involucral bracts have a differentiated margin that is often pale or reddish; Bothriocline laxa N. E. Br. C Immature heads; Vernonia potamophila Klatt. D Image of herbarium specimen (PRE). See Appendix C for citation details.

Figure 2. Illustrations: A Baccharoides adoensis (Sch. Bip. ex Walp.) H. Rob. B Bothriocline aggregata Hutch., note: this taxon is not found in southern Africa C Ethulia conyzoides L. f., note: lack of pappus; and D Gymnanthemum koekemoerae H. Rob. & V. Funk, note: broad involucral bracts without a high midrib. See Appendix C for citation details.

Figure 3. Scanning electron electron micrographs from three collections of acetolyzed echinolophate Baccharoides pollen showing variations in spine shape from acute to markedly blunt. A-H. Baccharoides anthelmintica (L.) Moench. A polar view B Equatorial view C Lateral view D Near polar view E Equatorial view F Fractured grain G Lateral view H Equatorial view I Fractured grain. (A-C, USDA P. I. 283729; D-F, Cooray 70031701 R; G-I, Koelz 7469). [Views from Robinson and Skvarla (2010); Figure 1 B = original Figure 1 G; Figure 1 C = original Figure 1 H; and Figure 1 H = original Figure 1 J.]