Lapidia apicifolia Roque & S.C. Ferreira, 2017

Roque, Nádia, Ferreira, Silvana C. & Berg, Cássio Van Den, 2017, Lapidia, a new monotypic genus of Asteraceae (Eupatorieae) from Brazil, and its phylogenetic placement, Phytotaxa 291 (1), pp. 1-16 : 6-14

Lapidia apicifolia Roque & S.C. Ferreira , sp. nov.

Type:— BRASIL. Bahia: Morro do Chapéu, Cachoeira do Ferro Doido , 11°37 ʹ 40.5 ʺ S, 41°00 ʹ 1.4 ʺ W, 900 m alt., 16 September 2015, Staudt, M. G. & Barres, L. 74 (holotype: ALCB!; isotypes: HUEFS!, RB!, SPF!, US!). Fig. 1A–R , 2A–G .

Erect shrubs 2–4 m high, main axis of similar diameter as second and third-level axes, branches dichotomously and loosely ramified producing a forked branching system toward the apex. Stems striated, internodes 5–10 mm long, nodal region detached after the falling leaves, tomentose and with capitate glandular trichomes in younger parts, becoming glabrescent in older ones. Leaves opposite, decussate, somewhat fleshy, conduplicate, petioles 4–6 mm long, tomentose; blades 1.8–3 × 1.8–3.5 cm, orbicular to obovate, rounded to truncate at apex, dentate, less commonly denticulate on the upper half margin, cuneate to truncate at base, venation pinnate, veins tomentose, tector trichomes uniseriate and biseriate, glabrescent, with dense capitate glandular trichomes on both surfaces. Capitulescence lax and corymbiform at apex of branches; capitula pedicellate, pedicels 4–7 mm long, tomentose, bracteolate, bracteoles 5–10, 1–3 mm long, linear, tomentose. Capitula discoid, homogamous; involucres cylindrical-turbinate, 4–6 × 5–6 mm, involucral bracts 3-seriate, subimbricate, bracts 14–16, in 3 series, the outer ones 3 × 0.5 mm, linear-lanceolate, tomentose, the inner one 4–4.5 × 1 mm oblanceolate, acuminate, tomentose, margins scarious, revolute at maturity, glabrescent, green; receptacle flat, slightly convex, glabrous. Flowers 18–20, bisexual, corolla tubulose, 5-lobed, white, 8–10 mm long, corolla throat 4 mm long, white, corolla tube 1–2 mm long, glabrous, corolla lobe deltate, with erect, capitate glandular trichomes on abaxial surface, otherwise glabrescent; anthers ca. 1.5 mm long, exserted from the corolla, connective-appendage oblong, rounded, as long as or slightly longer than wide, purple base rounded, anther-collars cylindrical, involute at female stage; styles 6–7 mm long, glabrous, not enlarged at base, style branches linear, densely papillose on sterile portion (1.5–2 mm long), stylopodium annuliform. Cypselae cylindrical, 5-ribbed, sparsely pilose (trichomes biseriate) along the ribs, surfaces glabrescent; carpopodium small, annuliform; pappus of 20–25 persistent bristles in one series, fused at the base, distinct in size, 2–4 mm long, apex purple or white and purple on apex.

Etymology: —The species epithet is related to the leaves positioned only at the apex of the branches.

Phenology: —Flowering time in May, September to November, mostly in the rainy season.

Distribution and Habitat: — Lapidia apicifolia is restricted to rocky fields areas in Morro de Chapéu municipality, Chapada Diamantina , Bahia. In the region, the species is widely distributed but is always associated with rocky outcrops ( Fig. 2A ).

Conservation Status: —The species is considered critically endangered (CR) based on the criteria and sub-criteria B1 a,b (i, ii, iii, iv) of IUCN (2001), i.e. fragmented and endemic populations occurring in one conservation unit but threatened by human impact (tourism) and fire during the dry season.

Phylogenetic placement: — The phylogenetic analysis based on the ITS and trnL-trnF regions recovers a topology similar to Rivera et al. (2016a). Most of our taxon sampling falls within the clade named by the authors as the “CAFE clade” ( Fig. 3 ).

Taking into account our trees, we can find two well-supported clades (Z and W) ( Fig. 3 ) that include small genera (1 to 9 species) with restricted distributions. In Clade W, we recovered two monophyletic clades. The first includes Bejaranoa , Conocliniopsis , and Dasycondylus , sister to Prolobus , a monotypic genus from maritime vegetation in the coast of Brazil. The second clade includes genera from the Chapada Diamantina : Bahianthus ( Fig. 4A–B ), Catolesia ( Fig. 4C ), and Morithamnus ( Fig. 4D–E ). The new genus Lapidia is placed as sister group of these three with high support. This clade is composed of loosely branched shrubs of 2 to 4 m high ( Fig. 2A , 4A,D ), with receptacles flat to convex and a persistent pappus of bristles (except Catolesia ) ( Table 2). In this clade, the plants are more robust, the leaves are lax (except Catolesia , Fig. 4C ) and alternate or opposite and decussate. Stems, leaves and involucral bracts are viscid ( Bahianthus and Morithamnus ) or, if not, trichomes (tomentose indumentum) are developed ( Lapidia ), to protect against both solar radiation and loss of water.

Clade Z comprises Agrianthus ( Fig. 5A,B ), Arrojadocharis ( Fig. 5C ), Bishopiella , Lasiolaena ( Fig. 5D–F ), Semiria ( Fig. 6A–B ) and Stylotrichium ( Fig. 6C–D ) genera. Unlike clade W, most of the species in this group are ericoid shrubs of 0.3–2 m high ( Fig. 5B,D ), with the leaf blades reticulate beneath, the receptacles convex ( Fig. 6B ) to conical (paleaceous or not), and the pappus of bristles and tending towards to be defective or absent ( Fig. 6B ) ( Table 3).

These preliminary results indicate the most genera previously attributed to Gyptidinae , such as Agrianthus Candolle (1836: 125) , Arrojadocharis Mattfeld (1930: 1053) , Bishopiella King & Robinson (1981: 218) , Lasiolaena King & Robinson (1972c: 185) , Semiria Hind (1999a: 425) , Stylotrichium Mattfeld (1923: 436) , Bejaranoa King & Robinson (1978: 52) , Conocliniopsis King & Robinson (1972a: 308) , Dasycondylus King & Robinson (1972d: 188) , Prolobus King & Robinson (1982: 386) , Bahianthus King & Robinson (1972b: 312) , Catolesia Hind (2000: 942) , Morithamnus King et al. (1979: 452) and Litothamnus King & Robinson (1979: 79) , are clustered in closely related clades, together with some Ageratinae, Ageratum fastigiatum and Acritopappus King & Robinson (1972e: 401) , also in a manner similar to the results of Rivera et al. (2016a).

Considering the recent molecular phylogenies including most of endemic genera of Eupatorieae from Brazil and the present one, the majority of the monophyletic groups that emerged cannot be recognized. We believe there is clearly a strong incongruence between molecular-based phylogenies and the previous morphological circumscription of subtribes and genera. For this reason, new systematic efforts (deep morphology sensu Stuessy 2003), including taxonomic revisions, assessment of new micromorphological characters and population genetic studies should be conducted in order to reassess the characters previously selected and their significance in the evolutionary history of these groups.

Taxonomic comments:— Lapidia is a sister group of the clade including Bahianthus , Catolesia and Morithamnus . Similarities of the capitulescence, receptacle and pappus (see Table 2) indicate that Lapidia is most similar morphologically to Morithamnus and Bahianthus . Despite this, in addition to the phylogenetic justification, several morphological characters are distinct enough to recognize Lapidia as a separate genus. Morithamnus is composed of two species and its representatives are shrubs which are well branched from the base, with stems, leaves and involucre viscid, relatively large leaves (to 15 cm long), which are alternate to opposite, with decurrent petioles, capitulescence withering with age and becoming overtopped by sub-floral innovations, involucre 2-seriate, bracts sub-equal and flowers 25–100 per head ( Fig. 4D–E ) ( King & Robinson 1987). Although the phyllotaxy can be similar, Lapidia apicifolia differs from Morithamnus by the habit (forked branching system toward the apex), being not viscid, leaves smaller, capitulescence erect when mature and lower number of flowers, characters strongly distinctive of the new species. On the other hand, Bahianthus is represented by a single species, Bahianthus viscosus ( Sprengel 1820: 277) King & Robinson (1972b: 312) ( Fig. 4A–B ), and presents erect shrubs that are loosely ramified from the base, leaves distinctly petiolate and capitulescence lax and corymbiform similar to Lapidia apicifolia . However, Bahianthus differs by the stem, leaves and involucre viscid, leaves alternate (vs. opposite decussate) and corolla with resin ducts.

Additional Specimens Examined (Paratypes): — BRAZIL. Bahia: Chapada Diamantina, Morro do Chapéu , 11º35’29’’ S, 41º12’28’’ W, 1200 m alt., 24 August 1998, Bautista & Rodriguez-Oubiña 2483 ( HRB) ; trilha para o Ventura , 11º33’ S, 41º09’ W, 07 September 2002, Guedes et al. 9828 ( ALCB) ; Cachoeira do Ferro Doido , 24 October 2003, Guedes et al. 10769 ( ALCB) ; idem, 03 September 2004, Roque et al. 1114 ( ALCB) ; trilha para o Ventura , 903 m alt., 11º37’70’’ S, 41º00’07’’ W, 04 September 2004, Roque et al. 1136 ( ALCB) ; Farm Jacobina , 11º 28’18’’ S, 41º13’52’’ W, 1097 m alt., 09 September 2006, Gonçalves & Souza 121 ( HUEFS) ; Morrão , torre da televisão, 11º 35’63’’S, 41º 12’8’’W, 1297 m alt., 08 September 2007, Melo et al.5061 ( HUEFS) ; Cachoeira do Ferro Doido , 921 m alt., 11º37’69’’ S, 41º00’05’’ W, 09 November 2007, Roque et al. 1659 ( ALCB) ; idem, 895 m alt., 23 May 2008, Roque et al. 1772 ( ALCB) .

Figures

FIGURE 1. Lapidia apicifolia Roque & S.C. Ferreira. A. Flowering branch. B. Tomentose indumentum at apex of the branches. C–D. Tector trichomes uniseriate and biseriate. E. Leaf with truncate apex. F. Leaf with serrate margin. G. Capitate glandular trichomes on blade. H. Head pedicellate with bract at peduncle. I. Bracteole. J. Outer bract. K–L. Inner bracts. M. Flat and glabrous receptacle. N. Corolla. O. Anther. P.Style. Q. Cypselae with bristles fused at base and with varying lengths. R. Geminate trichome from cypselae (drawn from the holotype by Natanael Nascimento dos Santos).

FIGURE 2. Lapidia apicifolia Roque & S.C. Ferreira. A. The rocky fields habitat with individuals of the species highlighted (red arrows). B–C. Terminal branches showing leaves opposite-decussate, petiolate, and blade conduplicate. D. Shape and abaxial surface of the leaf. E. Head showing purple colored anther appendages. F. Heads showing green involucral bracts, white corollas, and purplish pappus bristles. G. Fruits in dispersal. (Photographs:A, D, F–G: N.Roque, B–C, E: L.Barres).

FIGURE 3. Majority-rule 50% consensus tree of a Bayesian analysis to study the phylogenetic placement of Lapidia apicifolia among selected taxa of the “CAFE clade” (according to Rivera et al. 2016a) (Eupatorieae,Asteraceae), based on a combined matrix with sequence data from the internal transcribed spacer (ITS1 and ITS2) of the nuclear ribosomal DNA and the trnL–trnF plastid region (trnL intron, trnL-trnF spacer). Branch colors follow the same color scheme of Rivera et al. (2016a), and the values above branches correspond to the posterior probabilities calculated from the 18,000 trees obtained in the analysis after excluding burn-in.

FIGURE 4. Endemic genera of Eupatorieae in the Chapada Diamantina, Bahia state (Clade W). A–B. Bahianthus viscosus R.M.King & H.Rob. A. Fruits in dispersal. B. Flowers in anthesis. C. Catolesia huperzioides Roque et al. Flowering branch with dense spiral of leaves. D–E. Morithamnus crassus R.M.King & H.Rob. D. Habit. E. Buds and flowers in anthesis. (Photographs: A–B: L.Moura; C. A.A.Conceição; D–E: N.Roque).

FIGURE 5. Genera of Eupatorieae sympatric with Lapidia (Clade Z) in the Chapada Diamantina, Bahia state. A. Agrianthus myrtoides Mattf. B. Agrianthus giulietiae D.J.N.Hind. C. Arrojadocharis santosii R.M.King & H.Rob. D–E. Lasiolaena blanchetii (Sch.Bip. ex Baker) R.M.King & H.Rob. F. Lasiolaena duartei R.M.King & H.Rob.: bicolored leaves. (Photographs: A: N.Roque; B: L.Moura; C–F: V.Amorim).

FIGURE 6. Genera of Eupatorieae sympatric with Lapidia (Clade Z) in the Chapada Diamantina, Bahia state. A–B. Semiria viscosa D.J.N.Hind. A. Habit. B. Detail of head, showing convex, epaleaceous receptacle, and epappose cypselae. C. Stylotrichium glomeratum Bautista et al. D. Stylotrichium sucrei R.M.King & H.Rob. (Photographs: A–C: V.Amorim; D: S.C.Ferreira).