A new species of Boyania (Melastomataceae) from Guyana Abstract, Michelangeli F. A. It, Guyana. Rheedea 2022 2023-03-02 32 4 288 294 BRHXB Michelang. Michelang. 2022 [159,562,1469,1496] Magnoliopsida Melastomataceae Boyania Plantae Myrtales 1 289 Tracheophyta species kenwurdackii sp. nov.     Type: GUYANA,  Cuyuni-Marazuni, 2nd and 3rd escarpments (of four) of Kamakusa Mt., upper west-facing slopes below summit,  1330 m, N 5°52’55.2”, W 60°06’34.6”,  08.06.2012(fl),  K. J. Wurdack, E. A. Tripp, A. Radosavljevic &  J. Ralph5869 (holo NY[ NY04239396!]; iso K [K000370697], P [P00950851!], US[ n.v.]). Creeping to climbing herbs to small shrub, terrestrial or growing on fallen trunks or rocks, adventitious roots occasionally present. Stems obscurely quadrangular to flattened when young, glabrescent to pubescent, the trichomes mostly eglandular, but mixed with some glandular, 0.7–1.1 mmlong, appressed, the older stems glabrescent and terete, nodes with a membranous, irregular flap c. 1.3 mmwide. Leaves opposite, usually isophyllous, occasionally anisophyllous, then the smaller leaf 1/3-1/5 the size of the larger one; petioles in isophyllous nodes or large leaves 3–8 cmlong and up to 3.5 mmacross., in smaller anisophyllous leaves 5–12 mmlong, in all cases densely pubescent, trichomes simple, up to 2.5 mmlong, appressed; leaf blades ovate to elliptic, 6.5–13 × 3.8–8.5 cm, chartaceous, base obtuse to broadly acute, apex acute to acuminate, margins serrulate and sparsely ciliate, the trichomes simple, up to 1 mmlong; abaxial surface with sparse minute sessile glands, the primary and secondary veins pubescent, trichomes up to 0.8 mmlong, appressed, mostly eglandular, but with some glandular trichomes, higher order veins with mixed minute sessile glands and simple trichomes up to 0.2 mmlong; adaxial surface with sparse minute sessile glands, otherwise glabrescent or dense to sparsely strigulose with smooth trichomes up to 0.8 mmlong; venation acrodromous with 2–3 pairs of secondaries basal, the outer pair considerably thinner, tertiary veins straight, spaced every 3–5 mm, higher order veins forming areolae 2–4 mmwide. Inflorescence terminal, with a 4–9 cmlong peduncle, with a pair of bracts near the middle, glabrous, with 3–4 verticillate branches, each of them a scorpiod cyme; bracteoles lanceolate, 2–3 mmlong, margins ciliate at the apex, persistent in flower, but late caducous; pedicels 3–4.5 mmlong at anthesis, up to 13 mmlong in fruit. Flowers 4–merous; hypanthium campanulate, 2.5–3 mmlong, 2.1–2.3 mmwide at the torus, sparsely covered by minute sessile glands. Calyx 1.6–1.8 mmlong; tube c. 8 mmlong, lobes broadly deltoid with a blunt slightly cucullate apex, 0.8–1 mmlong, the outer tooth reduced to a stubby round bump, the outer surface with glands similar to the hypanthium. Petals 3–3.2 mmlong, thin and translucid when dry. Stamens 8, isomorphic; filaments 2.5–2.8 mmlong, glabrous; anthers subulate and slightly arcuate, 2.1–2.2 mmlong, opening by a minute pore, upright to slightly dorsally oriented, connective not prolonged belong the thecae, but with a dorsal flattened appendage 1.4–2.2 mmlong, and two ventral appendages c. 0.15 mmlong. Ovary fully to ½ inferior, 4– locular, with a collar c. 0.9 mmtall around the style, glabrous; style straight, projecting 2.5–2.8 mmabove the collar; stigma punctiform. Fruit capsular, terete but with 8 prominent ridges; seeds numerous (>50) per fruit, long pyramidal, 0.6–0.7 long, testa cells flat and with the anticlinal walls puzzle-shaped.   Fig. 1.  Boyania kenwurdackiiMichelang.: a. Flowering stem with distal leaves and inflorescences, with close up of stem node; b. Young inflorescence; c. Branch with old inflorescence remnant; d. Inflorescence remnant with persistent bracteoles; e. Petiole apex and leaf base; f. Stem node and flap. g. Young inflorescence; h. Flowers and bud in lateral view, mature flower (right) with petals removed; i. Flower in longitudinal section (left) through the ovary and with petals and stamens removed, (right) through the hypanthium with petals and some stamens removed; j. Antesepalous stamens in lateral (left), dorsal (middle) and frontal (right) views (a–f from Michelangeli2489; g–j from K.J. Wurdack, E.A. Tripp, A. Radosavljevic & J. Ralph5869; drawn by Bobbi Angell).   Fig. 2.Scanning electron microscopy images of seeds of  Boyania kenwurdackiiMichelang.: a. Entire seed; b. Detail of testa (both from C.E. Zartman, M.M. Pombo, Y.H. Glen & C. Perry9387).  Flowering & fruiting: Flowering and fruiting plants have been collected in both in March and June, but there are no collections outside of these months.  Habitat:  Boyania kenwurdackiigrow in the understory of moist forests in the foothills and mid elevations of the Pakaraima mountains of the Guayana Shield in central Guyanaat elevations between 225 mand 1330 m( Fig. 3).   Fig. 3. Arc Gis map with distribution points of  Boyania kenwurdackiiMichelang.and  Boyania ayangannaeWurdackin Guyana.  Distribution: Endemic to Guyana.  Etymology: The specific epithet honors Ken Wurdack, Curator at the National Museum of Natural History of the Smithsonian Institution, who has collected in some of the most remotes corners of Guyana, including the typeof this new species.  Specimens examined:  Boyania kenwurdackii   Michelang: GUYANA,  Potaro-Siparuni. Kaieteur National Park, upper Mure Murebasin,  480–490 m, N 5°16’19.56”, W 59°30’53.28”,  25.03.2014(fl.),  F.A. Michelangeli& N. Zarine2486 ( BRG, NY, US);  Marina Falls,  449 m, N 5°22’43.2”, W 59°29’33.3”,  28.03.2011(fl.),  C.E. Zartman, M.M. Pombo, Y.H. Glen& C. Perry9356 ( INPA);  Amalia Fallsto V  4, 225 m, N 5°20’40”, W 59°32’06”,  30.03.2011(veg.),  C. E. Zartman, M.M. Pombo, Y.H. Glen& C. Perry9368 ( INPA, US);   Ibid.,  30.03.2011(fl.),  C.E. Zartman, M.M. Pombo, Y.H. Glen& C. Perry9387 ( INPA, US); V4, N 5°22’40”, W 59°32’00”,  31.03.2011(fl.),  C.E. Zartman, M.M. Pombo, Y.H. Glen& C. Perry9404 ( INPA, US).   Boyania ayangannaeWurdack: GUYANA,  Cuyuni-Mazaruni, Pakaraima Mts, ascent and transect 4 kmalong NE plateau of Mt. Ayanganna,  1100–1500 m, N 5°24’, W 59°57’,  06.11.1992(fl buds),  T.W. Henkel147 ( BRG, NY, US);  Pakaraima Mountains, Kumarau Falls on Kurupung River, 0.5–1.5 kmSW on forest trails,  350 m, N 6°05’, W 60°21’,  31.07.1992(veg),  B. Hoffman2237 ( NY, US);  Pakaraima Mountains; ascent and transect 4 kmalong NE plateau of Mt. Ayanganna,  1100– 1500 m, N 5°24’25”, W 59°57’13”,  06.11.1992(fr),  B. Hoffman3236 ( NY, US);  Pakaraima Mountains;  1–4 kmNW of Mt. Ayangannaon outer toe slopes of mountain,  800–1100 m, N 5°25’, W 60°0’,  09.11.1992(fr),  B. Hoffman3308 ( BRG, NY, U, US);  Membaru-Kurupung Trail, Pakaraima Mts.,  1000 m, 29.10-  04.11.1951(veg),  B. Maguire32405 (B, NY, US, VEN[ paratypes]);  Mt. Ayanganna, NE side of, upper Mazaruni Riverbasin,  800–915 m, N 5°23’, W 59°57”,  14.08.1960(fl.),  S.S. Tillet45000 (K, NY, US[ paratypes]);   Ibid  16.08.1960(fl.),  S.S. Tillet45151 ( NY[ paratype]);   16.08.1960(fl.), S.S. Tillet45152 (G[ isotype], K[ isotype], NY[ isotype], US[ holotype]).   Potaro-Siparuni, Wokomung, base camp & vic., upper Potaro Riverregion,  1070–1160 m, N 5°5’, W 59°50’,  30.06.1989(fl.),  B.M. Boom8993 ( NY, US);  Mt. Wokomung, easternmost pinnacle of massif,  1524 m, N 5°05’34.4”, W 59°50’13.3”,  30.06.2003(fl.),  H.D. Clarke10344 ( BRG, NY[2], US);  Mt. Wokomung, NE facing slopes above second of four escarpments,  1400 m, N 5°5’56”, W 59°50’16”,  01.07.2003(fl.),  H.D. Clarke10389 ( NY[2], US);  Pakaraima Mts, Mt. Wokomung, Wusupubaru Creek, 2 kmfrom juncture with Suruwabaru Creek,  975–1125 m, N 5°03’, W 59°53’,  13.02.1993(fr),  T.W. Henkel1340 ( BRG, NY, US);  Pakaraima Mts, Mt. Wokomung.W slope on sub-plateau near head of Mo-toymabaru Creek,  1150–1200 m, N 5°04’, W 59°53’,  11.11.1993(fr),  T.W. Henkel4286 ( BRG, CAS, FLAS, NY, U, US);   Ibid,  11.11.1993(fl bud, fr),  T.W. Henkel4291 ( BRG, CAS, FLAS, INPA, NY, U, US);  PakaraimaMts-Mt. Wokomung, summit ridge of Ka-mie-wah pinnacle NE to S pinnacle, “Little Ayanganna”, 1550–1650, N 5°04’, W 59°52’,  17.11.1993(fl.),  T.W. Henkel4436 ( BRG, CAS, FLAS, NY, US);  Pakaraima Mtns; upper Irengwatershed, Sukabi River, Kurdah Falls, lower E branch,  685 m, N 5°06’, W 59°97’,  20.10.1994(fl.),  P.A. Mutchnick129 ( US).  Conservation status: It is known from only six collections made in the last 12 years, only one of which is inside a national park. Moreover, four of the paratypeshave been collected in areas that have been identified as future dam sites for hydroelectric power. The Extent of Occurrence ( EOO) is 474.3 km 2and the Area of Occupancy ( AOO) is 20 km 2with a total of 4 locations. Based on the low number of locations, the EOO and AOO and the fact that some of the areas are likely to be developed in the near future, it is recommended that  Boyania kenwurdackiibe considered Endangered under criteria B1ab(iii)+ B2ab(iii) ( IUCN, 2022).  Notes: Superficially,  Boyania kenwurdackiiclosely resembles  B. ayangannae, and indeed all the specimens assigned here to the new species had been initially determined as the latter. However, the two species differ by the number of petals, hypanthium indumentum, the size of the petals, and the size and morphology of the anther appendages (see diagnosis). Additionally, the ovary in  B. kenwurdackiiseems to range from ½ to fully inferior and it is 4-locular, while it is superior and 3-locular in  B. ayangannae; however, these characters are based on limited dissections for both species. Furthermore,  B. kenwurdackiiis easily distinguished from  B. colombiana, the third species in the genus, by the leaf bases (obtuse to broadly acute vs. cordate), and the anthers dorsal connective appendages (present vs. absent). Although  B. kenwurdackiiand  B. ayangannaeboth grow in central Guyana, and relatively close to each other, they have not been collected in the same locality.  Boyania ayagannaehas been mostly collected around Mount Ayanganna and Mount Wokomung at 800–1400 m, and once farther west along the Kurupung River at 350 m(Fig. 4).  Boyania kenwurdackiihas been mostly collected at 225–480 mon tributaries of the Potaro River farther north of Mount Ayanganna, and once (the type), at 1300 min Kamakusa Mountain. When Wurdack (1964)described  Boyaniahe placed it in the expanded Sonerileaeand noted that among neotropical members of the tribe it most closely resembled  DiplarpeaTrianaor  MonolenaTriana ex Benth. & Hook.f. However, it is notable that he also remarked that it actually shared more characters with Old World Sonerileae.  Diplarpeahas now been synonymized under  TriolenaNaudin, and both  Triolenaand  Monolena form thetribe Trioleneae, an exclusively neotropical group not part or sister to the Sonerileaeas currently defined ( Bacci et al., 2020). It should be noted that the collection cited as  B. ayangannaein recent phylogenetic analyses ( Bacci et al., 2019; Wurdack & Michelangeli, 2019; Maurin et al., 2021; Penneys et al., 2022) is actually one of the paratypesof  B. kenwurdackii.Moreover, when more than one species of  Boyaniahave been included in phylogenetic studies the genus is not recovered as monophyletic, with both terminals close to the base of the tribe, although most of the branches in between these taxa have low or moderate support. 2012-08-06 K. J. Wurdack & E. A. Tripp & A. Radosavljevic Guyana 1330 5.882 Kamakusa Mt. 1 -60.109608 1 289 1 Cuyuni-Marazuni holotype 2014-03-25 BRG, NY F. A. Michelangeli & N. Zarine Guyana Michelang 485 5.2721004 upper Mure Mure 1 -59.5148 Kaieteur National Park 3 291 1 Potaro-Siparuni 2011-03-28 INPA C. E. Zartman & M. M. Pombo & Y. H. Glen & Perry Guyana 449 5.378667 1 -59.492584 3 291 1 Potaro-Siparuni 2011-03-30 INPA C. E. Zartman & M. M. Pombo & Y. H. Glen & C. Perry United States of America 4225 4 292 5.3444448 Amalia Falls 21 -59.535 3 291 1 2011-03-30 INPA C. E. Zartman & M. M. Pombo & Y. H. Glen & Perry United States of America Ibid. 4 292 1 2011-03-31 INPA C. E. Zartman & M. M. Pombo & Y. H. Glen & Perry United States of America 5.377778 US 21 -59.533333 4 292 1 1992-06-11 BRG, NY T. W. Henkel Guyana 1300 5.4 Mt. Ayanganna 1305 -59.95 Pakaraima Mts 4 292 1 Cuyuni-Mazaruni 1992-07-31 NY B. Hoffman United States of America 350 6.0833335 Kumarau Falls on Kurupung River 1305 -60.35 Pakaraima Mountains 4 292 1 1992-06-11 NY B. Hoffman United States of America 1300 5.4069448 Mt. Ayanganna 21 -59.953613 Pakaraima Mountains 4 292 1 1992-09-11 BRG, NY B. Hoffman United States of America 950 5.4166665 Pakaraima Mountains 1305 -60.0 4 292 1 1951-04-11 NY, VEN B. Maguire United States of America 1000 Pakaraima Mts. Membaru-Kurupung Trail 4 292 1 paratype 1960-08-14 NY S. S. Tillet United States of America 858 5.383333 upper Mazaruni River 1305 -59.95 Mt. Ayanganna 4 292 1 paratype 1960-08-16 NY S. S. Tillet United States of America Ibid 4 292 1 paratype 1960-08-16 NY Tillet United States of America US 4 292 4 isotype 1989-06-30 NY B. M. Boom United States of America Potaro-Siparuni 1115 5.0833335 upper Potaro River 1305 -59.833332 Wokomung 4 292 1 isotype 2003-06-30 BRG, NY H. D. Clarke United States of America 1524 5.092889 Mt. Wokomung 1 -59.837025 4 292 1 isotype 2003-01-07 NY H. D. Clarke United States of America 1400 5.098889 Mt. Wokomung 21 -59.837776 4 292 1 isotype 1993-02-13 BRG, NY T. W. Henkel United States of America Pakaraima Mts 1050 5.05 Wusupubaru Creek 1305 -59.883335 Mt. Wokomung 4 292 1 isotype 1993-11-11 BRG, CAS, FLAS, NY T. W. Henkel United States of America Pakaraima Mts 1175 5.0666666 Mo-toymabaru Creek 1305 -59.883335 Mt. Wokomung. 4 292 1 isotype 1993-11-11 BRG, CAS, FLAS, INPA, NY T. W. Henkel United States of America Ibid 4 292 1 isotype 1993-11-17 BRG, CAS, FLAS, NY T. W. Henkel United States of America 5.0666666 Wokomung 1305 -59.866665 Pakaraima 4 292 1 isotype 1994-10-20 P. A. Mutchnick United States of America Pakaraima Mtns 685 5.1 Sukabi River upper Ireng 4 292 1 isotype