Two new genera, Hoffmannanthus and Jeffreycia, mostly from East Africa (Erlangeinae, Vernonieae, Asteraceae)

Abstract Two genera of Vernonieae subtribe Erlangeinae with Type A pollen, 5-ribbed achenes, and blunt-tipped sweeping hairs on the styles are described as new, Hoffmannanthus with one species and with Vernonia brachycalyx O. Hoffm. as type, and Jeffreycia with five known species, with Vernonia zanzibarensis Less. as type. Vernonia abbotiana O. Hoffm. is neotypified and is an older name for V. brachycalyx.


Introduction
Th e dismantling of the overly broad concept of Vernonia Schreb. in the Old World was begun by Robinson (1999a). In that study, the primary point was fully established, that there are no true members of the genus Vernonia native to the Eastern Hemisphere. Th e genus Vernonia is almost entirely North American (Robinson 1999b). Still, acceptance of segregate genera would inevitably depend on establishment of a reasonably complete coverage of the tribe, defi ning properly phyletic segregates, and discovery of reasonable characteristics by which the segregates can be distinguished.
Th e present eff ort concentrates on a related group that contains a number of mostly African, woody perennial species of the subtribe Erlangeinae having 5-angled achenes, blunt-tipped sweeping hairs on the styles, and tricolporate type A pollen Jones 1977, 1979), also known as sublophate pollen (Skvarla et al. 2005). Two elements of this group are here described as new genera, Hoff mannanthus and Jeff reycia.

Methods
Specimens examined were from the U.S. National Herbarium in Washington, DC. Microscopic structures were examined mostly using material mounted in Hoyer's Solution (Anderson 1954). Preparation of pollen for scanning electron microscopy (SEM) consisted of acetolysis (Erdtman 1960) followed by the osmium-thiocarbohydrazide repeat procedure (Chissoe et al. 1995) and pulse sputter coating with a gold/palladium (60/40) target (Chissoe and Skvarla 1996). Examination was with a JEOL 880 (University of Oklahoma) SEM equipped with lanthanum hexaboride (LaB6) electron sources.

Results and discussion
Th e genera Hoff mannanthus and Jeff reycia, described here as new, are evidently closely related, but of these only Hoff mannanthus has had its DNA sequenced (Keeley et al. 2007). Th e available DNA sequence results place Vernonia brachycalyx O. Hoff m., the type of Hoff mannanthus, in a subclade within the subtribe Erlangeinae (Keeley and Robinson (2009). According to the DNA sequence, that part of the subtribe contains Vernoniastrum H. Rob. (Robinson 1999a), and somewhat more distantly, Orbivestus H. Rob. (Robinson 1999a(Robinson , 2009. Of these, Vernoniastrum diff ers by a more herbaceous habit, pointed sweeping hairs on the style branches, idioblasts of the achenes in transverse bands, and lophate, triporate pollen. Orbivestus has the same type of pollen as Hoff mannanthus, but the plant is more herbaceous, has heads in seriate or subscorpioid cymes, has nearly sessile T-shaped hairs on the stems, has strictly subimbricate and otherwise undiff erentiated bracts in its involucres, has narrowly rhomboid raphids in the walls of the achenes, and has pointed tips on the sweeping hairs of the style branches. Th e sweeping hairs occur along the entire outer surface of the style branches. Sequence data is lacking for Jeff reycia, but on the basis of structural evidence, Jeff reycia is considered closer to Hoff mannanthus than Vernoniastrum or Orbivestus. As shown in the review by Herz (1996), Jeff reycia (as Vernonia zanzibarensis) and Hoff mannanthus (as Vernonia brachycalyx) also share an unusual type of glaucolide derivative that has otherwise been reported only from Bothriocline (as B. amplifolia), all three genera evidently members of the Erlangeinae in the strict sense.
Th e typical element of the subtribe Erlangeinae with the genera Erlangea Sch. Bip., Bothriocline Oliv. ex Benth., and Cyanthillium Blume consists of herbaceous plants with mostly lophate, triporate pollen, symmetrically T-shaped hairs, and sharply pointed sweeping hairs on the styles. In contrast, the two genera described herein are shrubbier or weakly arborescent with sublophate, tricolporate pollen having a continuous perforated tectum between the colpi, simple or asymmetrical non-T-shaped hairs, and blunt tips on the sweeping hairs.
Th e two new genera, Hoff mannanthus and Jeff reycia (Fig. 1), share one feature found in many Old World Vernonieae, namely the sweeping hairs which are restricted to the branches of the style and do not extend onto the upper shaft, a feature otherwise a defi ning characteristic of the tribe Vernonieae and the subfamily Cichorioideae. Jeff reycia may be the most extreme in this character, with the sweeping hairs usually failing to even reach the bases of the style branches.
Th ese genera are treated here together to allow a more eff ective direct comparison. Th e most obvious diff erences between Hoff mannanthus and Jeff reycia are found in the hairs of the stems, the shape of the leaves, and in details of the corolla lobes. Th e hairs on the stems of Hoff mannanthus have a rather long, uniseriate multicellular stalk with an elongate, asymmetrically mounted horizontal cap cell at the tip, these hairs being what could be called L-shaped (Fig. 1D). In contrast, the hairs on the stems of Jeff reycia species are simple and unbranched. Th e leaves of Hoff mannanthus have long petioles below the distinct basal acumination of the blade, and have no auricles on the blades (Fig. 1A). Th e leaves of all Jeff reycia except the typical variant of the type species, J. zanzibarensis (Less.) H. Rob., S. Keeley & Skvarla have short petioles and blades with auricles projecting laterally at the base (Fig. 1E, F, I-K). Th e corolla lobes in Hoff mannanthus are oblong-triangular, and usually recurved at maturity (Fig. 1B, C). Jeff reycia has corolla lobes that are strictly lanceolate, the sides not parallel in any part, but evenly convergent from the base to the tip (Fig. 1G, L). Th e lobes are erect though sometimes withered when dry, but never recurved. A less obvious diff erence is the tendency for the pappus bristles in Hoff mannanthus to be sordid or even rufous and broader in the distal half, while those of Jeff reycia tend to be white and narrowed above. Jones (1981) placed the type species of Hoff mannanthus, Vernonia brachycalyx O. Hoff m., in his Vernonia subsect. Strobocalyx S.B. Jones, among species now placed in the mostly African Gymnanthemum Cass. and in the mostly Asiatic and Malaysian genus Strobocalyx (Blume ex DC.) Spach. Jeff rey (1988) placed the species in his group 2 subgroup B, in an aggregate 3, distinguished by its persistent involucral bracts, 5-angled achenes, and ovate to cordate, non-panduriform leaves. Vernonia brachycalyx was not treated in the fi rst eff ort to resolve palaeotropical Vernonieae by Robinson (1999a). Relationships of the species of Hoff mannanthus are considered to be particularly close to Jeff reycia which was placed by Jeff rey (1988) in his group 2, subsection B, aggregate 2. Th e present study shows that the two genera share Type A sublophate pollen, 5-angled achenes with short raphids, and blunt sweeping hairs on the style branches. Like many of the Old World Vernonieae, the sweeping hairs in Hoff mannanthus are lacking on the upper shaft of the style, but unlike most Jeff reycia, are not lacking on the bases of the style branches. Both genera are most common in east Africa. It is concluded that the two genera described here as new are closely related to each other but distinct.  Th e second genus treated here, Jeff reycia, includes three of the species mistakenly placed in Gymnanthemum in the subtribe Gymnantheminae by Robinson (1999a), a genus from which the present group is now seen to be subtribally distinct. Among the most obvious diff erences are the presence in Gymnanthemum of a broad abaxial shield in the involucral bracts and the tendency for the inner involucral bracts to be deciduous in Gymnanthemum, instead of persistent as in Jeff reycia. A genus that is possibly closely related to Jeff reycia is the recently described Uniyala H. Rob. & Skvarla of India and Sri Lanka (Robinson and Skvarla 2009) with which Jeff erycia scarcely overlaps geographically, only through its one species in Sri Lanka. While superfi cially similar, Uniyala has a shrubbier habit with closely spirally inserted leaves, nonpanduriform bases of the blades, elongate raphids and thinner walled cells in the achene wall, and short tubes on the corollas and corolla lobes that are not strictly triangular.
An apparent additional distinction between Uniyala and both Jeff reycia and Hoffmannanthus is the pollen. In all three genera, the pollen is approximately the same size, ca. 30 μm in diam. when dry, up to 50 μm in diam. in fl uid, type A tricolporate or sublophate with a continuous perforated tectum between the colpi. However, in Uniyala the pollen has incipient muri more defi ned with fewer, larger incipient lacunae (Robinson and Skvarla 2009) than in the present group, where muri are obscure and the incipient lacunae are small and more numerous (Figs 2-5). Th e generic segregates of Vernonia in tropical Africa are only partially resolved. A treatment of all but two species in Southern Africa is nearly complete, but it does not include any close relatives of the two genera described here. Nevertheless, the presently recognized tropical African genera that have previously been placed in Vernonia can be partially distingushed by the following key. Its utility is limited by the number of segregates of tropical African Vernonieae that remain untreated.
Identification key to the segregate genera of Vernonieae of East Africa   Leaves alternate, petioles slender and 7-15 mm long below basal acumination of blade; blades ovate, 6-7 times longer than petiole, 5-10 cm long, 1.5-5.0 cm wide, base broadly obtuse to short-acute, narrowly acuminate at petiole, margins remotely denticulate to nearly entire, apex scarcely to gradually acuminate, surfaces pilosulous and with glandular dots, hairs sparser above, dense on larger veins; secondary veins pinnate, with ca. 6 weak secondary veins on each side of midrib, spreading at ca. 40-45° angles. Infl orescences broadly corymbiform, with branches elongate, mostly with small or insignifi cant bracteoles at bases; peduncles 2-30 mm long. Heads campanulate; involucre much shorter than fl orets at maturity; involucral bracts in 2-3 series, persistent, oblong-lanceolate, with acute to short-acuminate tips, puberulous outside, pale at base, midvein broadly greenish, percurrent at tip, lateral margins thinly membranous; receptacle scarcely convex, epaleate, epilose. Florets ca. 15 in a head, homogamous, bisexual; corollas violet to purple, narrowly funnelform, with long basal tube, throat short, lobes narrowly oblong-lanceolate, with glandular dots outside; anthers with triangular apical appendages; base of style slightly enlarged, style shaft glabrous, sweeping hairs on style branches elongate with rounded or blunt tips. Achenes 5-angled, with some glandular dots and short setulae, surface with sparse idioblasts and inner layer with small subquadrate or rounded raphids; pappus pale to sordid or rufous, 2 series, inner pappus of many capillary bristles that are slightly broader in distal half, outer pappus of short narrow scales. Pollen grains 40 μm in diam., Type A, sublophate. 2n = 20 (Jones 1982 Although not a type, the specimen led to a careful comparison with the original description of the species (Hoff mann 1894). Th e specimen was fi nally recognized as a Vernonia brachycalyx with unusually long peduncles, but almost certainly fi tting the description of V. abbotiana in all details except the peduncles and the supposedly deciduous inner involucral bracts. Th e inner involucral bracts of Vernonia brachycalyx are not deciduous, but the involucre is short, giving the appearance of a missing inner series. As for the density of the infl orescence in V. abbottiana, the original author, Hoff mann (1894) compared his species with Vernonia livingstoniana Oliv. & Hiern, which is a synonym of Gymnanthemum thomsonianum (Oliv. & Hiern) H. Rob. Th e latter species is not a close relative, but the reference to it in the original description indicates the kind of dense infl orescence. Such a dense infl orescence is unlike that in the Peter specimen, but it is very like typical material of Vernonia brachycalyx with which the Peter specimen is now identifi ed. Th e identifi cation might never have been made without the advent of the Peter specimen, but names such as V. abbotiana, dating from comparatively early in the study of tropical Africa, do need to have their identity resolved by some means, in this case by neotypifi cation. Personally, there is no doubt of the identifi cation provided here, and a neotype, that is an isolectotype of V. brachycalyx at the US National Herbarium is selected (Fig. 6), a specimen that matches the denser form of the infl orescence that is indicated by Hoff mann (1894). 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. Infl orescences 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 diff erentiated long, linear-lanceolate basal bracts, bracts, except at base, smooth outside, without median keel; receptacle scarcely convex, epaleate, epilose, with proturberant scars; fl orets 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 diff erentiated angles, with or without glands or setulae, with scattered idioblasts on surface sometimes in vertical series, inner cells of achene wall with distinct fi rm 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 fl attened on outer surface; outer series of short persistent scales, minute to 0.5 mm long. Pollen ca. 40 μm in diam. in fl uid, sublophate, tricolporate, with perforated tectum continuous between colpi.

Jeff reycia
Etymology. Th e new genus, Jeff reycia, honors the author of the study of the Vernonieae of East Tropical Africa (Jeff rey 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, Jeff rey (1988) included another three species in his aggregate, Vernonia bruceae C. Jeff rey, V. stuhlmanii O. Hoff m., and V. fi scheri O. Hoff m., but these have not been seen in this study and therefore are not included in the new genus. Of these, V. fi scheri O. Hoff m. (1895) and V. stuhlmannii O. Hoff m. (1898) are described with leaf bases truncate to subcordate, and both species are probably members of Jeff reycia, distinguished from the others by the appendages on the tips of their involucral bracts. However, V. 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 Jeff reycia recognized here, and any close relationship to Jeff reycia is doubtful.
Notes on morphology. Regarding the shape of the leaf base, while it is similar to cordate, Jeff rey (1988) refers to it as panduriform. Th e auricles result mostly from a constriction above the base of the leaf blade. Th is 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 V. zanzibarensis with panduriform bases on short-petiolate leaves, and it is apparently plants like these that have been interpreted by Jeff rey (1988) as hybrids between that species and Vernonia hildebrandtii Vatke. However, it is possible that such leaf blades are just a variant of V. zanzibarensis that has reverted to or retained the leaf form that is characteristic of all the other members of the genus.  (Grierson 1980: 131) refers to at least three (possibly fi ve) specimens, and this choice is narrowed here.
Key to the five species presently placed in the genus Jeffreycia