Two new genera, Hoffmannanthus and Jeffreycia, mostly from East Africa (Erlangeinae, Vernonieae, Asteraceae)
Author
Robinson, Harold
Department of Botany, MRC 166, National Museum of Natural History, Smithsonian Institution, P. O. Box 37012, Washington, DC., 20013 - 7012, USA
robinsoh@si.edu
Author
Keeley, Sterling C.
Department of Botany, University of Hawaii, Manoa, 3190 Maile aWay, # 101, Honolulu, Hawaii, 96822 - 2279, USA
Author
Skvarla, John J.
Department of Botany and Microbiology, and Oklahoma Biological Survey, University of Oklahoma, Norman, Oklahoma, 73018 - 6131, USA, deceased 2 March 2014
Author
Chan, Raymund
Department of Botany, MRC 166, National Museum of Natural History, Smithsonian Institution, P. O. Box 37012, Washington, DC., 20013 - 7012, USA
text
PhytoKeys
2014
2014-07-18
39
49
64
http://dx.doi.org/10.3897/phytokeys.39.7624
journal article
http://dx.doi.org/10.3897/phytokeys.39.7624
1314-2003-39-49
0777C824BF1C8660EA7FA516AF3DB456
576227
Jeffreycia H. Rob., S.C. Keeley & Skvarla
gen. nov.
Type.
Vernonia zanzibarensis
Less.
Small to moderate-sized; branching, often scrambling shrubs; stems woody, with narrow solid pith; hairs simple, without cap-cells, sometimes forming loose tomentum. Leaves alternate; petioles distinct, short to elongate; blades ovate to elliptic or panduriform usually with basal auricles, abruptly delimited from petiole at the base, 2.5 to ca. 11 cm long, ca. 1.5-7.5 cm wide, margins crenate or serrate, apices acute to scarcely acuminate, rarely obtuse, upper surface sparsely pilosulous to hispidulous, lower surface sparsely pilosulous to tomentellous, with many glandular dots; secondary veins 4-6 on each side, with unusual somewhat meandering course, spreading at 45-60° angles. Inflorescences terminal, with branches alternate and usually ascending at 30° angles or less, usually with minute bracteoles, sometimes primary bracteoles larger and foliiform; heads crowded at ends of longer branches, with distinct short peduncles; involucral bracts persistent, subimbricate in ca. 4-5 series or with differentiated long, linear-lanceolate basal bracts, bracts, except at base, smooth outside, without median keel; receptacle scarcely convex, epaleate, epilose, with proturberant scars; florets 5-40 in a head; corollas purplish, 5-11 mm long, with some glandular dots outside, few or no hairs below tips, basal tube slender, half as long as the
corolla
, throat half as long as the limb, ca. as long as the lobes, lobes strictly narrowly lanceolate, with sides straight from base to apex, erect, not recurving, sometimes with stiff hairs at tip; anther thecae without glands, calcarate at base, with narrow tails; endothecial cells with
out
obvious nodes; apical appendages narrowly lanceolate; style with basal node; sweeping hairs with blunt tips, restricted to branches, often lacking for some distance above bases of branches. Achenes 2-4 mm long, with 4 or 5 poorly differentiated angles, with or without glands or setulae, with scattered idioblasts on surface sometimes in vertical series, inner cells of achene wall with distinct firm cell walls, containing small subquadrate raphids; carpopodium stopper-shaped or somewhat turbinate and asymmetrical, with many series of subquadrate, thick-walled cells; pappus white, with inner series capillary, often deciduous, 4.5-7.0 mm long, gradually narrowed to tips, somewhat flattened on outer surface; outer series of short persistent scales, minute to 0.5 mm long. Pollen ca. 40
µm
in diam. in fluid, sublophate, tricolporate, with perforated tectum continuous between colpi.
Etymology.
The new genus,
Jeffreycia
, honors the author of the study of the
Vernonieae
of East Tropical Africa (
Jeffrey 1988
) whose work has been one of the most helpful in resolving the tribe in Africa.
Number of species.
Five species are currently placed in the genus.
In addition to the species listed below,
Jeffrey (1988)
included another three species in his aggregate,
Vernonia bruceae
C. Jeffrey,
Vernonia stuhlmanii
O. Hoffm., and
Vernonia fischeri
O. Hoffm., but these have not been seen in this study and therefore are not included in the new genus. Of these,
Vernonia fischeri
O. Hoffm. (1895) and
Vernonia stuhlmannii
O. Hoffm. (1898) are described with leaf bases truncate to subcordate, and both species are probably members of
Jeffreycia
, distinguished from the others by the appendages on the tips of their involucral bracts. However,
Vernonia brucaea
is described with "foliis ellipticis vel lanceolatis basi late cuneatis vel rotundatis". Not stated is whether that leaf base is as abrupt at the insertion on the petiole as in all the species of
Jeffreycia
recognized here, and any close relationship to
Jeffreycia
is doubtful.
Notes on morphology.
Regarding the shape of the leaf base, while it is similar to cordate,
Jeffrey (1988)
refers to it as panduriform. The auricles result mostly from a constriction above the base of the leaf blade. This character is lacking only in those specimens of
Vernonia zanzibarensis
Less. that have longer petioles. Some specimens combine long hairs at the apices of the corolla lobes as in
Vernonia zanzibarensis
with panduriform bases on short-petiolate leaves, and it is apparently plants like these that have been interpreted by
Jeffrey (1988)
as hybrids between that species and
Vernonia hildebrandtii
Vatke. However, it is possible that such leaf blades are just a variant of
Vernonia zanzibarensis
that has reverted to or retained the leaf form that is characteristic of all the other members of the genus.