435 research outputs found
Pseudosenegalia riograndensis Seigler & Ebinger 2017, comb nov.
No full text2. Pseudosenegalia riograndensis (Atahuachi & L. Rico) Seigler & Ebinger, comb nov. Basionym: Acacia riograndensis Atahuachi & L. Rico, Kew Bull. 62: 605. 2007. TYPE: Bolivia. Cochabamba: Prov. Campero, Pasorapa, en la bajada de Buenavista hacia el Rıo Grande, 1447 m, 27 Dec. 2004, J. R. I. Wood, M. Atahuachi & M. Mercado 21251 (holotype, BOLV; isotypes, K! [barcode] K 00503018, K! [bc] K 005033019, LPB [bc] LPB0 0 0 0 6 7 6, MEXU [bc] MEXU0128851). Figure 11. Tree to 12 m tall; bark nearly white, smooth to shallowly fissured; twigs orange to reddish brown, not flexuous, terete, glabrous; short shoots present at some nodes, 0.4–1 mm long, with a few leaves attached; prickles absent. Leaves alternate, also clustered at short shoots, 15–55 mm long; stipules light brown, linear, symmetrical, flattened, straight, herbaceous, 1–2.5 X 0.1–0.2 mm, glabrous, usually persistent; petiole adaxially grooved, 4–13 mm long, glabrous; petiolar gland solitary, located just below to nearly between the lowermost pinna pair, sessile; orbicular to oval, 0.4–1.1 mm across, apex depressed, glabrous, sometimes absent; rachis adaxially grooved, 5–40 mm long, glabrous, an orbicular gland 0.3–0.7 mm across between the uppermost 1 to 2 pinna pair, apex depressed, glabrous; pinnae 3 to 7 pairs/leaf, 9– 2 0 mm long, 3–1 2 mm between pinna pairs; paraphyllidia absent; petiolule 0.9–2.1 mm long; leaflets 12 to 26 pairs/pinna, opposite, 0.8–1.7 mm between leaflet pairs, linear, 1.2–2.9 X 0.5–0.9 mm, glabrous, lateral veins not obvious, 1 vein from the base, base oblique, truncate on one side, margins lightly ciliate, apex obtuse, midvein subcentral. Inflorescence a loosely 40- to 90-flowered cylindrical spike, 28–60 X 12–18 mm, solitary from the leaf axils; peduncles 5–16 X 0.3–0.8 mm, glabrous; receptacle not enlarged; involucre absent; floral bracts spatulate, 0.7–1.1 mm long, ciliate, persistent. Flowers sessile, white; calyx 5-lobed, 1.5–2.2 mm long, lightly puberulent; corolla 5-lobed, 3.5–6 mm long, glabrous to puberulent, lobes 1/5 the length of the corolla; stamens 100 to 140; stamen filaments 7.5–9.5 mm long, distinct; anther glands absent; ovary glabrous, stipe to 2.1 mm long. Legumes straight, flattened, not constricted between the seeds, oblong, 95–130 X 10–15 mm, coriaceous, transversely striated, glabrous, eglandular, dehiscent along both sutures; stipe 6–11 mm long; apex acute, short beaked; seeds uniseriate, with no pulp, light brown, ellipsoid, strongly flattened, 9–11 X 6–7 mm, smooth; pleurogram U-shaped, 3–5 mm across. Habitat and distribution. Pseudosenegalia riograndensis is known locally in seasonally dry tropical forest at about 1300 m in the Rio Grande valley below Pasorapa, Provence Campero, Cochabamba, Bolivia. Phenology. Pseudosenegalia riograndensis flowers from November through December. IUCN Red List category. Pseudosenegalia riograndensis is assessed as Data Deficient (DD) at this time (IUCN, 2001). This species is apparently rare and is only known from two collections, the type and one other from a restricted region in Bolivia suggesting that the species may at least be Vulnerable (VU), perhaps Endangered (EN). Specimen examined. BOLIVIA: Cochabamba: Campero, Bosque Termotropical inferior de Neocardenasia herzogiana y Schinopsis haenkeana, 1300 m, 24 Nov. 1999, C. Antezana 1325 (NY).Published as part of Seigler, David S., Ebinger, John E., Riggins, Chance W., Terra, Vanessa & Miller, Joseph T., 2017, Parasenegalia and Pseudosenegalia (Fabaceae): New Genera of the Mimosoideae, pp. 180-205 in Novon 25 on pages 201-203, DOI: 10.3417/2015050, http://zenodo.org/record/256146
Parasenegalia visco Seigler & Ebinger & Riggins & Terra & Miller 2017, comb. nov.
No full text6. Parasenegalia visco (Lorentz ex Griseb.) Seigler & Ebinger, comb. nov. Basionym: Acacia visco Lorentz ex Griseb., Abh. Königl. Ges. Wiss. Göttingen. 19: 135, 279. 1874. [Pl. Lorentz. 87. 18 74.] Senegalia visco (Lorentz ex Griseb.) Seigler & Ebinger in Seigler et al., Phytologia 88(1): 78. 2006. TYPE: Argentina. Catamarca: Fuerte de Andalgala ad rivulos, 13 Jan. 1872, P. G. Lorentz 34 0 (lectotype, designated here, GOET [image!] [11463]; isolectotypes, CORD [image!] [barcode] CORD00004860, SI [image!] [bc] SI001494). Figure 8. Acacia concinna Phil., Anales Univ. Chile 2: 170. 1870, nom. illeg., non Acacia concinna (Willd.) DC., Prodr. [A. P. de Candolle] 2: 464. 1825. TYPE: Argentina. Mendoza: in hortis, Philippi s.n. (lectotype, designated here, SGO [image seen] [barcode] SGO000002427, SGO photo at SI; isolectotypes, SGO fragm. at SI, SI photo at F! [27897], G, MO). Acacia platensis Manganaro, Anales Soc. Ci. Argent. 87: 128– 133, figs. 12, 13. 1919. Manganaroa platensis (Manganaro) Speg., Bol. Acad. Nac. Ci. 26: 254, pls. 255, 257, 265.1921. TYPE:Argentina (lectotype,designated by Cialdella, 1984: 96, LP [barcode] LPS24314). Acacia polyphylla Clos in Gay, Fl. Chil. 2: 254. 1846, nom. illeg., non Acacia polyphylla DC., Cat. Pl. Horti Monsp., 74. 18 13. Lysiloma polyphyllum Benth., Trans. Linn. Soc. London 30: 535. 1875. TYPE: Chile. ‘‘Pcia. Coquimbo, San Isidro, 1836, an culta’’ (lectotype, designated here, SGO [image seen]; isolectotypes, BR! [barcode] BR0000005117031, K [image seen] [bc] K000530853, P [image seen] [bc] P02142747. P [image seen] [bc] P03641821, P [image seen] [bc] P0 3 6 4 1 8 2 2, P [image seen] [bc] P03641823, P [image seen] [bc] P03641824, SGO fragm. at SI [image seen] [bc] SI661495). Acacia riparia Kunth b [var.] angustifoliola Kuntze, Revis. Gen. Pl. 3(3): 47. 1898. TYPE: Bolivia. Santa Cruz: Sierra de Santa Cruz, 2000 m, C. E. O. Kuntze s.n. (lectotype, designated here, NY! [barcode] NY00001542; isolectotype, F!). Manganaroa subsericea Speg., Bol. Acad. Nac. Ci. 26: 267. 1921 [1923]. TYPE: Argentina. Salta: ‘‘In dumetis montanis praeandinis, locis Quebrada de Guachipas et Pampa grande vocatis,’’ C. L. Spegazzini s.n. (lectotype, designated by Seigler et al., 2006a: 78, LP (LPS-14305) [image seen] [barcode] LP001053; isolectotype, LP [bc] LP001054). Tree to 25 m tall; bark not seen; twigs light to dark reddish brown, not flexuous, terete, glabrous to lightly puberulent; short shoots absent; prickles absent. Leaves alternate, 60–170 mm long; stipules light to dark brown, linear, symmetrical, flattened, straight, herbaceous, 2–6 mm long, 0.4–0.7 mm wide near the base, usually glabrous, tardily deciduous; petiole adaxially grooved, 25–45 mm long, lightly puberulent; petiolar gland solitary, anywhere along the petiole, sessile, usually oblong, 0.7–2.7 mm long, apex flattened to depressed, glabrous; rachis adaxially grooved, 35–130 mm long, puberulent, an oval to orbicular gland 0.5–1.2 mm across between the uppermost 1 to 2 pinna pairs, apex flattened to depressed, glabrous; pinnae (3)4 to 11(14) pairs/leaf, 40–70 mm long, 8–21 mm between pinna pairs; paraphyllidia 0.5–1.2 mm long; petiolule 1.1–2.2 mm long; leaflets 25 to 50 pairs/pinna, opposite, 0.8–2.1 mm between leaflet pairs, oblong, 3–7 X 0.8–2.1 mm, appressed pubescent on both surfaces, lateral veins sometimes obvious, 1 to 3 veins from the base, base oblique, truncate on one side, margins lightly ciliate, apex narrowly acute to acuminate, midvein submarginal, bluish purple beneath. Inflorescence a densely 40- to 75-flowered globose head 16–23 mm across, 1 to 3 in the leaf axils; peduncles 15–40 X 0.5–0.8 mm, puberulent; receptacle enlarged, not elongate, globose; involucre a small bract scattered along the peduncle, early deciduous, sometimes absent; floral bracts spatulate, 1.2–1.9 mm long, puberulent, early deciduous. Flowers sessile, white; calyx 5-lobed, 1.7–2.8 mm long, puberulent; corolla 5-lobed, 3.2– 4.3 mm long, lightly puberulent, lobes 1/5 the length of the corolla; stamens 60 to 90; stamen filaments 8– 11 mm long, distinct; anther glands present; ovary glabrous to rarely pubescent, stipe to 1 mm long. Legumes straight, flattened, not constricted between the seeds, oblong, 80–150 X 18–30 mm, chartaceous, transversely striate, glabrous to lightly puberulent, minute purple glands commonly present, dehiscent along both sutures; stipe 4–10 mm long; apex obtuse, the beak to 10 mm long; seeds uniseriate, no pulp, light brown, oval to oblong, strongly flattened, 9–13 X 7–10 mm, smooth; pleurogram U-shaped, 1.2–2.2 mm across. Habitat and distribution. Parasenegalia visco has been collected from seasonally wet mountains, deciduous forests, riparian forests, yungas, disturbed second-growth forests, and thickets, from 750 to 3000 m in northern Argentina, through Bolivia, northern Chile, and Peru. The taxon is commonly cultivated in Peru as well as where native (Rico Arce, 2007). Phenology. Parasenegalia visco flowers from October through January. Local names and uses. Local names include visco, arca, viscote, viscote negro, viscote blanco, and visite (Rico Arce, 2007). Parasenegalia visco is commonly cultivated for its wood. IUCN Red List category. Parasenegalia visco is assessed as Data Deficient (DD) at this time (IUCN, 2 0 0 1) but is an abundant species of southern South America and is commonly cultivat- ed in Argentina, Chile, Peru, Uruguay, and South Africa as an ornamental and as a fast-growing tree for cabinet wood (Rico Arce, 2 0 0 7). Parasenegalia visco is also known from numerous collections from Argentina and Bolivia and is probably of Least Concern (LC). Discussion. Parasenegalia visco is a large South American tree that is commonly cultivated and economically important for wood products. The globose inflorescence more than 16 mm across, along with the small leaflets (3–7 X 0.8–2.1 mm) with bluish purple midveins, distinguish this species from other members of the genus. Paul G. Lorentz was a German botanist and professor at the University of Córdoba, Argentina, until 1 8 74. His vascular plant collections at GOET were the sources for species described by Grisebach in his Plantae Lorentzianae (1 8 7 4) and Symbolae ad Floram Argentinam (1 8 7 9). The collection Lorentz 3 4 0 at GOET has an original label identifying the species as Acacia visite, which corresponded to the first name used by Grisebach in Plantae Lorentzianae (1 87 4: 1 3 5), which was emended in this same work to Acacia visco (1 87 4: 2 7 9). Although no collection was specified in the protologue, Lorentz can be assumed to be the collector (Stafleu & Cowan, 1 9 7 6: 1 0 1 1, 1 98 1: 1 5 7) for species similarly described by Grisebach. The lectotype at GOET (1 1 4 63) bears an original label with the spelling as Acacia Visite. This species was cited as introduced into South Africa as Acacia visite Griseb. (Ross, 1 9 7 5). Two common names were mentioned in the protologue by Grisebach (1874) for his Acacia species number 269 (1874: 135), as ‘‘[n]omen vernac. Visite, Visco.’’ These vernacular names were a source of confusion for the species epithet. On page 135, Grisebach described the new species as ‘‘269. Acacia Visite Gr.,’’ but this was emended by him in the same work on page 279 under ‘‘Verbesserungen’’ (Improvements), as ‘‘S. 135 nr. 269 statt [instead of] A. Visite Gr. lies [read] A. Visco Lor. in litt.’’ It is this emendation that indicated Grisebach’s intent to change the epithet to the other vernacular name, acknowledging Lorentz as well. Grisebach’s intent was further supported in his later treatment of Acacia in Symbolae ad Floram Argentinam (1879: 122), where the species was also cited as ‘‘ A. Visco Lor. mscr. – Syn. A. Visite Pl. Lor. [269],’’ with the number corresponding to the species number in the previous 1874 treatment in his Plantae Lorentzianae. The specimen chosen as the lectotype of Acacia concinna is representative of that species and is from the home institution (SGO) of Philippi, the describing author. No specimen was cited by Manganaro (1919: 128– 129) in the protologue for Acacia platensis, although she did note the species as ‘‘visto cultivada esta planta en Buenos Aires y en La Plata....’’ Spegazzini (1921) transferred the name to the genus Manganar- oa Speg. based on Manganaro’s study. Cialdella cited the specimen with the word ‘‘typus’’ written on it, presumably used by both previous investigators, LP [barcode] LPS24314, as the holotype. We interpret this as a de facto lectotypification. Although the name Mimosa polyphylla Clos was written on the type specimen of Acacia polyphylla Clos in Gay, apparently this name in Mimosa was never published. If this name were published, it would be the oldest name for Parasenegalia visco, but still illegitimate. The SGO lectotype chosen for A. polyphylla is representative of the species and is from the home institution of the describing author. Kuntze (1898: 47) described Acacia riparia var. angustifoliola from two countries as ‘‘Bolivia: Sierra de Santa Cruz 2000 m. and Argentina: Provinz Santiago.’’ Of these two possible syntypes, the NY (barcode NY0 0 0 0 1 5 4 2) sheet from Bolivia was annotated by Seigler and Ebinger (2009) as the holotype, emended here as the lectotype. A syntype of Manganaroa subsericea from Argentina (prov. Buenos Aires, La Plata, Jardín Botanico ‘‘Facultad de Agron.’’), also identified as the collection C. L. Spegazzini s.n., is at LP (LPS- 14305) (Cialdella, 1984). Specimens examined. ARGENTINA. Catamarca: Andalgala, 1 9 5 0 m, 2 8 Nov. 19 4 6, C. A. O’Donnell 4 1 8 3 (S); S of Cumbre de las Lajos, 1 7 0 0 m, 2 6 Nov. 1 9 4 6, B. Sparre 9 7 6 (S); Choya–El Tofo, 1 8 0 0 m, 2 8 Nov. 1 9 4 6, B. Sparre 1 0 0 3 (S); Andalgala, 2 8 Nov. 1 9 46, E. Wall s.n. (MO). Córdoba: 4 km N of Sarmiento, 1 0 8 0 m, 1 2 Oct. 1 9 8 8, J. Aronson 7 6 4 6 (MO); Puesto del Paraiso, 4 Jan. 1 8 9 7, T. Stuckert 1 2 7 1 (G); Villa Rosario, 1 4 Nov. 1 9 0 2, T. Stuckert 1 1 9 6 3 (G). Jujuy: El Volcan, 1 3 May 1 8 7 3, Lorentz & Hieronymus 7 1 4 (S), 7 5 9 (S); Purmamarca, 1 1 Jan. 1 9 7 1, A. Krapovickas & C. L. Cristóbal 1 7 6 3 7 (WIS); 2 km de Volcan camino a Lozano, 2 3 4 0 m, 1 0 Feb. 1 9 9 8, O. Morrone, N. B. Deginani, A. M. Cialdella & L. M. Giussani 2 4 0 1 (MO); Sierra de Calidegus, 8 0 0 m, 1 5 Oct. 1 9 2 7, S. Venturi 5 3 8 2 (CAS, GH, MO); San Pedro, 7 5 0 m, 2 0 Oct. 1 9 2 9, S. Venturi 9 7 4 4 (CAS, MO); Purmamarca, 2 8 Oct. 1 9 8 2, E. M. Zardini & M. L. Pochettino 1 5 6 4 (MO). La Rioja: 1 0 km S of Famatina, RN 4 0, 1 4 5 0 m, 1 4 Mar. 1 9 9 3, S. M. Botta & D. C. Miconi 5 9 0 (MO); Famatina, 1 6 0 0 m, 1 1 Jan. 1 9 4 7, J. H. Hunziker 1 8 1 5 (MO); Castro Barros, 1 5 km W of Anillaco, 1 9 8 0 m, 3 0 Mar. 1 9 9 2, J. H. Hunziker & J. C. Gamerro 1 2 48 0 (MO); Los Duraznillas, 7 5 0 m, 3 Nov. 1 9 4 7, I. Huasi 3 5 (GH). Salta: 2 0 km S of Salta, 1 1 2 0 m, 5 Nov. 1 9 8 8, J. Aronson 7 6 9 0 (MO); Cafayate, 8 Nov. 1 9 7 8, A. L. Cabrera, S. Botto, C. Ezcurra, A. M. Ragonese & M. Vazques A. 2 9 7 0 3 (MO); Cafayate, 8 Jan. 1 9 7 2, A. Krapovickas & C. L. Cristóbal 2 0 7 2 7 (WIS); Chorrillos, 2 1 1 0 m, 1 7 Jan. 1 9 41, T. Meyer 3 5 6 0 (GH); San Fernando, 6 May 1 9 4 7, T. Meyer 1 2 4 5 7 (RSA, US); Iruya, 2 7 0 0–2 8 0 0 m, 8 Nov. 1 9 8 8, L. J. Novara, T. Adzet & J. Masso 8 1 9 8 (B, M); Salta, 5 Nov. 1 9 8 2, E. M. Zardini 1 6 1 9 (MO); Iruya, 1 0 Feb. 1 9 8 3, E. M. Zardini 1 9 6 5 (GH); Iruya, 1 0 Feb. 1 9 8 3, E. M. Zardini, M. L. Pochettino, J. Hurrell, C. Iudica & D. Ramadori 1 9 6 5 (MO). Tucuman: San Javier, 1 0 50 m, 4 Nov. 1 9 7 8, S. A. Renvoize, M. Wilmot-Dear & R. Kiesling 3 3 6 4 (MO); Francas a Zarate, 7 8 0 m, 1 2 Oct. 1 9 2 5, Schreiter 6 8 5 9 0 (BM); Tapia, 2 7 Oct. 1 9 7 6, D. S. Seigler & F. Vervoorst 1 0 1 0 8A (EIU, ILL); Tapia, 2 7 Oct. 1 9 7 6, D. S. Seigler & F. Vervoorst 1 0 1 1 4 (ILL, MO); 1 3.8 km SE of Amaicha del Valle on rd. to Tafi del Valle, 2 4 0 0 m, 4 May 1 9 8 5, J. C. Solomon 1 3 5 3 6 (MO); Yerba Buena, 7 0 0 m, 1 9 2 6, S. Venturi 6 7 (GH); Tapia, 7 5 0 m, 2 4 Oct. 1 9 2 3, S. Venturi 2 4 7 6 (CAS, MO); Cerro del Campo, 8 0 0 m, 4 Nov. 1 9 2 8, S. Venturi 7 4 5 2 (GH). BOLIVIA. Chuquisaca: Comunidad Pitatorillas, 27 7 4 m, 2 2 Sep. 2 0 0 7, M. Jiménez, E. Cervantes & F. Janko 3 6 1 (ILL, MO). Cochabamba: camino hacia Omereque, Km. 1 8 6, 2 0 4 0 m, 2 7 Oct. 1 9 9 3, C. Antezana 3 9 7 (MO); vic. of Cochabamba, 1 8 9 1, M. Bang 9 2 1 (MO); city of Cochabamba, 1 8 Nov. 1 9 8 2, L. Bohs 1 9 9 0 (F, GH); near Arani, 2 7 7 0 m, May 1 9 4 7, M. Cardenas & H. C. Cutler 3 8 8 3 (GH); Arani, 2 7 0 0 m, 2 9 Nov. 1 9 7 9, T. Feuerer 6 9 4 2 (HBG); park, Colina de San Sebastian, Cochabamba, 2 57 5 m, 2 4 Nov. 1 9 8 4, M. Nee 3 0 3 5 2 (MO); 6 km NE of El Convento, 2 5 4 6 m, 1 3 Mar. 2 0 0 3, L. Rico 1 5 5 9 (MO); Mizque, 2 0 2 5 m, 2 7 Dec. 2 0 0 2, L. Rico & T. Windsor-Shaw 1 1 9 9 (MO); Carrasco, 2 1 0 0 m, 1 1 Feb. 1 9 8 7, J. C. Solomon & M. Nee 1 6 0 2 4 (ILL, MO, NY). La Paz: Hacienda Huajchilla, 1 8 km SE of La Paz, 3 0 0 0 m, 1 8 Dec. 1 9 8 6, J. C. Solomon 1 5 7 7 7 (ILL, MO). Potosí: Charcas, 2 5 0 0 m, A. Uzedo 5 (HBG). Santa Cruz: Saipina, 18 0 0 m, 2 2 Oct. 1 9 94, J. Balcazar 6 9 (MO); hills E of Salta, 1 3 0 0–1 4 0 0 m, 2 2 Sep. 1 9 8 5, A. Gentry & C. Palacia 5 1 7 3 1A (MO); rd. from Mairana to Postrervalle, 7.7 km SSE of Quirusillas, 1 75 0 m, 3 1 Dec. 1 9 9 7, M. Nee 4 7 6 6 0 (ILL, MO); 3.7 km NW of bridge over Rio Comarapa at Comarapa, 2 0 0 0 m, 2 4 Nov. 1 9 9 9, M. Nee 5 0 5 9 3 (MO); 5 km SW of Comarapa on rd. to Chilón, 1 7 7 5 m, 2 6 Nov. 1 9 9 9, M. Nee 5 0 6 6 8 (MO); 4 0 km E of Comarapa, 1 7 4 0 m, 2 2 Oct. 1 9 9 1, M. Saldias & T. Pennington 1 4 7 9 (MO); 1 1 km de Comarapa, 2 7 4 0 m, 3 July 1 9 8 9, D. N. Smith, V. García & M. Buddensiek 1 3 6 0 7 (MO); Comarapa, 2 0 0 0 m, 2 6 Oct. 1 9 2 8, J. Steinbach 8 5 7 8 (A, GH, S); Huasacañada, 2 0 5 0 m, 1 5 Feb. 1 9 9 0, I. G. Vargas C. 4 2 9 (MO); Huasacanãda, 2 0 5 0 m, 5 Nov. 1 9 8 9, I. G. Vargas C. 3 3 3 (MO); Huasacañada, 5 km S of Vallegrande, 2 0 5 0 m, 3 Nov. 1 9 9 0, I. G. Vargas C. 8 0 4 (MO); Huasacañada, 5 km S of Vallegrande, 2 0 5 0 m, 1 5 May 1 9 9 2, I. G. Vargas C. 1 3 9 8 (MO); Vallegrande, 1 3 km pasando Pucara en el camino hacia el Puente del Río Grande, 1 1 5 0 m, 2 1 Oct. 2 0 0 1, I. G. Vargas, C. Jordan & A. Vargas J. 6 6 2 2 (ILL, MO). Tarija: 6 km SW of Chocloca, 2 0 0 0 m, 2 5 Mar. 1 9 7 9, St. G. Beck 7 5 1 (US); Tarija, 1 9 2 0 m, 1 0 Jan. 1 9 7 9, C. Ruiz s.n. (US); 3 0 km de Tarija (vers Entre Rios), 1 8 5 0 m, 3 Dec. 1 9 7 5, J. R. de Sloover 3 8 1 (MO). CHILE. Tarapaca: Arica Prov., 1st Region, Codpa, 1 8 2 0 m, 1 2 Feb. 1 9 8 9, J. Aronson 7 7 5 8 (MO). PERU. Lima: Lima, 2 8 Nov. 1 9 6 6, S. S. Tillett 6 6 1 1-5 7 (A) (cultivated). Tacna: Alrededores de Tacna, 3 0 Oct. 1 9 4 8, R. Ferreyra 4 0 7 1 (MO, US).Published as part of Seigler, David S., Ebinger, John E., Riggins, Chance W., Terra, Vanessa & Miller, Joseph T., 2017, Parasenegalia and Pseudosenegalia (Fabaceae): New Genera of the Mimosoideae, pp. 180-205 in Novon 25 on pages 194-196, DOI: 10.3417/2015050, http://zenodo.org/record/256146
The nature of the crust beneath the Afar triple junction: Evidence from receiver functions
No full textThe Afar depression is an ideal locale to study the role of extension and magmatism as rifting progresses to seafloor spreading. Here we present receiver function results from new and legacy experiments. Crustal thickness ranges from ?45 km beneath the highlands to ?16 km beneath an incipient oceanic spreading center in northern Afar. The crust beneath Afar has a thickness of 20–26 km outside the currently active rift segments and thins northward. It is bounded by thick crust beneath the highlands of the western plateau (?40 km) and southeastern plateau (?35 km). The western plateau shows VP/VS ranging between 1.7–1.9, suggesting a mafic altered crust, likely associated with Cenozoic flood basalts, or current magmatism. The southeastern plateau shows VP/VS more typical of silicic continental crust (?1.78). For crustal thicknesses <26 km, high VP/VS (>2.0) can only be explained by significant amounts of magmatic intrusions in the lower crust. This suggests that melt emplacement plays an important role in late stage rifting, and melt in the lower crust likely feeds magmatic activity. The crust between the location of the Miocene Red Sea rift axis and the current rift axis is thinner (<22 km) with higher VP/VS (>2.0) than beneath the eastern part of Afar (>26 km, VP/VS < 1.9). This suggests that the eastern region contains less partial melt, has undergone less stretching/extension and has preserved a more continental crustal signature than west of the current rift axis. The Red Sea rift axis appears to have migrated eastward through time to accommodate the migration of the Afar triple junction
The Built Environment: Cities, Water Systems, Energy, and Transport
No full textThe climate is changing, and the Eastern Europe and Central Asia (ECA) region is vulnerable to the consequences. Many of the region's countries are facing warmer temperatures, a changing hydrology, and more extremes, droughts, floods, heat waves, windstorms, and forest fires. This book presents an overview of what adaptation to climate change might mean for Eastern Europe and Central Asia. It starts with a discussion of emerging best-practice adaptation planning around the world and a review of the latest climate projections. It then discusses possible actions to improve resilience organized around impacts on health, natural resources (water, biodiversity, and the coastal environment), the 'unbuilt' environment (agriculture and forestry), and the built environment (infrastructure and housing). The last chapter concludes with a discussion of two areas in great need of strengthening given the changing climate: disaster preparedness and hydro-meteorological services. This book has four key messages: a) contrary to popular perception, Eastern Europe and Central Asia face significant threats from climate change, with a number of the most serious risks already in evidence; b) vulnerability over the next 10 to 20 years is likely to be dominated by socioeconomic factors and legacy issues; c) even countries and sectors that stand to benefit from climate change are poorly positioned to do so; and d) the next decade offers a window of opportunity for ECA countries to make their development more resilient to climate change while reaping numerous co-benefits
Magma-assisted rifting in Ethiopia
No full textThe rifting of continents and evolution of ocean basins is a fundamental component of plate tectonics, yet the process of continental break-up remains controversial. Plate driving forces have been estimated to be as much as an order of magnitude smaller than those required to rupture thick continental lithosphere1, 2. However, Buck1 has proposed that lithospheric heating by mantle upwelling and related magma production could promote lithospheric rupture at much lower stresses. Such models of mechanical versus magma-assisted extension can be tested, because they predict different temporal and spatial patterns of crustal and upper-mantle structure. Changes in plate deformation produce strain-enhanced crystal alignment and increased melt production within the upper mantle, both of which can cause seismic anisotropy3. The Northern Ethiopian Rift is an ideal place to test break-up models because it formed in cratonic lithosphere with minor far-field plate stresses4, 5. Here we present evidence of seismic anisotropy in the upper mantle of this rift zone using observations of shear-wave splitting. Our observations, together with recent geological data, indicate a strong component of melt-induced anisotropy with only minor crustal stretching, supporting the magma-assisted rifting model in this area of initially cold, thick continental lithosphere
Insights Into Fault-Magma Interactions in an Early-Stage Continental Rift From Source Mechanisms and Correlated Volcano-Tectonic Earthquakes
No full textStrain in magmatic rifts is accommodated by both faulting and dike intrusion, but little is known of the frequency of dike intrusions in early-stage rifts. We use a new earthquake data set from a dense temporary seismic array (2013–2014) in the ~7-Myr-old Magadi-Natron-Manyara section of the East African Rift, which includes the carbonatitic Oldoinyo Lengai volcano that erupted explosively in 2007–2008. Full moment tensor analyses were performed on M > 3.4 earthquakes (0.03- to 0.10-Hz band) that occurred during the intereruptive cycle. We find two opening crack-type and various non-double-couple earthquake source mechanisms and interpret these as fluid-involved fault rupture. From waveform analysis on the nearest permanent seismic station, we conclude that similar rupture processes probably occur over eruptive and intereruptive cycles. The repeated and dynamically similar fluid-involved seismicity, along with intrabasinal localization of active deformation, suggests that significant and persistent strain is accommodated by magmatic processes, modulated by tectonic cycles
Low-Frequency hybrid earthquakes near a magma chamber in Afar: quantifying path effects
No full textAreas of active volcanism contain elaborate velocity structures that complicate interpretations of earthquake source mechanisms. We examine the spectral characteristics of 805 earthquakes that immediately followed a large volume basaltic dike intrusion and associated silicic flank eruption of Dabbahu volcano in the Afar Depression as recorded on near-source seismometers. We use these results to quantify the contribution of scattering and attenuation to the observed spectra of low-frequency hybrid and volcano-tectonic earthquake clusters from beneath Dabbahu volcano and around the dike zone. We find strong variations in the signal amplitude and frequency content of earthquakes recorded at stations separated by as little as 2 km, caused by preferential attenuation of high frequencies depending on the vantage point. These observations imply that there are large impedance contrasts near the cooling, solidifying, and recently intruded dike. We estimate the intrinsic absorption attenuation coefficient, QI, and inverse scattering length, g0, averaged over a 300-sq-km area beneath Dabbahu. Our results are consistent with the highest attenuation coefficients from studies of volcanic provinces in Italy (QI-1 ? 0.02, g0?0.1 km-1 for a signal at 2 Hz). The magnitude of these two parameters indicates there are large impedance contrasts present in the area due to the recent intrusion of magma and associated fracturing
Abstracts of papers not published in full
No full textAbstracts included:John E. Ebinger. Hybridization between Elymus virginicus and E. hystrixRichard J. Jensen. Numerical Classification: Cladistics or Phenetics?Gayton C. Marks. A Unique Ruderal Plant Association in the Central Panhandle of Florid
Comparison of dike intrusions in an incipient seafloor-spreading segment in Afar, Ethiopia: Seismicity perspectives
No full textOceanic crust is accreted through the emplacement of dikes at spreading ridges, but the role of dike intrusion in plate boundary deformation during continental rupture remains poorly understood. Between 2005 and 2009 the ?70 km long Dabbahu?Manda Hararo rift segment in Ethiopia has experienced 14 large volume dike intrusions, 9 of which were recorded on temporary seismic arrays. A detailed comparison of the seismic characteristics of the seismically monitored dikes is presented with implications for dike intrusion processes and magmatic plumbing systems. All of the migrating swarms of earthquakes started from a <5 km radius zone at the middle of the Dabbahu?Manda Hararo segment, and traveled northward and southward along the rift axis. Small magnitude earthquakes associated with the margins of the propagating dike tips are followed by the largest magnitude, primarily low?frequency earthquakes. The seismic moment distributions show >80% of energy is released during the propagation phase, with minimal seismic energy release after the dike propagation ceases. We interpret that faulting and graben formation above the dikes occurs hours after the passage of the dike tip, coincident with the onset of low?frequency earthquakes. Dike lengths show no systematic reduction in length with time, suggesting that topographic loading and stress barriers influence dike length, as well as changes in tectonic stress. The propagation velocities of all the dikes follow a decaying exponential. Northward propagating dikes had faster average velocities than those that propagated southward, suggesting preconditioning by the 2005 megadike, or ongoing heating from a subcrustal magma source north of the midsegment
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