A new species of climbing Chamaedorea (Arecaceae) from Chiapas, Mexico

Chamaedorea tacanensis (Arecaceae), a new species from the Tacaná Volcano Biosphere Reserve, Chiapas, Mexico, is described based on morphological and phylogenetic data. It is morphologically similar to C. elatior, the only other climbing species in the genus. However, C. tacanensis is distinguished by having linear pinnae (lanceolate in C. elatior), petioles emerging glaucous (glabrous in C. elatior), and longer rachises, blades and peduncles than C. elatior. Also, C. tacanensis has pinnate-leaved seedlings and juveniles, whereas they are simple or bifid in C. elatior. The two taxa form separate monophyletic groups. Geographically, C. tacanensis is found in tropical montane cloud forests of the Pacific slope whereas C. elatior mostly occurs in lowland tropical forests of the Atlantic slope. Chamaedorea tacanensis has been recorded in only three localities: two in the Tacaná Volcano Biosphere Reserve, Mexico, and one in San Marcos, Guatemala. Further floristic studies in surrounding areas might better clarify the geographic distribution range of this species.

Taxonomic Revision of the Neotropical Genus Werneria (Compositae, Senecioneae)

Werneria is a neotropical genus belonging to the tribe Senecioneae (Compositae) that is mainly distributed through the highlands of the Andes. Only a single species, W. nubigena, has a trans-Andean distribution and reaches the Tacaná Volcano in southern Chiapas (Mexico). The traditional concept of Werneria was significantly narrowed at the end of the twentieth century after segregating several species and accommodating these mostly in the genus Xenophyllum. As currently circumscribed, it includes rosettiform or scapiform species characterized by usually displaying involucral bracts that are fused at the base, supplementary bracts commonly absent, usually radiate but sometimes discoid or disciform capitula, white or yellow ray corollas (when present), a balusterform filament collar, and style branches that are truncate and have a crown of sweeping hairs. The first modern, comprehensive revision of this genus recognizing 27 species is presented here. Werneria heteroloba and W. obtusiloba are synonymized with W. pinnatifida, and W. acerosifolia is synonymized with W. staticifolia. Moreover, five infraspecific names and three supraspecific names are synonymized. Detailed descriptions, distribution maps, photographs of living plants (except for W. cochlearis), and a list of all specimens examined are provided for each accepted species. An identification key to the species and a list of exsiccatae are also given. Eight species are illustrated, two of them for the first time. The following names are lectotypified: Werneria brachypappa Sch. Bip., W. caespitosa Wedd., W. calyculata Turcz., W. canaliculata Sch. Bip., W. carnulosa A. Gray, W. densa Benth., W. disticha Kunth, W. glaberrima Phil., W. glandulosa Wedd., W. heteroloba f. microcephala Rockh., W. mandoniana Wedd. ex Klatt, W. nubigena Kunth, W. nubigena var. caulescens Wedd., W. nubigena var. dombeyana Wedd., W. orbignyana Wedd., W. orbignyana var. breviradiata A. Gray, W. orbignyana var. longifolia Rockh., W. pectinata Lingelsh., W. plantaginifolia Wedd. ex Klatt, W. pygmaea var. caespitosa Wedd., W. rhizoma J. Rémy, W. solivifolia Sch. Bip., W. staticifolia Sch. Bip., W. staticifolia var. celmisioides Wedd., and W. villosa A. Gray. The names Werneria knocheae Perkins, W. minima Walp., W. minima var. pygmaea Walp., and W. stuebelii Hieron. are neotypified, and an epitype is designated for W. glandulosa. At the supraspecific level, the name Werneria sect. Integrifoliae Rockh. is typified.

Taxonomic Revision of the Neotropical Genus Werneria (Compositae, Senecioneae)

<i>Werneria </i>is a neotropical genus belonging to the tribe Senecioneae (Compositae) that is mainly distributed through the highlands of the Andes. Only a single species, <i>W. nubigena</i>, has a trans-Andean distribution and reaches the Tacaná Volcano in southern Chiapas (Mexico). The traditional concept of <i>Werneria </i>was significantly narrowed at the end of the twentieth century after segregating several species and accommodating these mostly in the genus <i>Xenophyllum</i>. As currently circumscribed, it includes rosettiform or scapiform species characterized by usually displaying involucral bracts that are fused at the base, supplementary bracts commonly absent, usually radiate but sometimes discoid or disciform capitula, white or yellow ray corollas (when present), a balusterform filament collar, and style branches that are truncate and have a crown of sweeping hairs. The first modern, comprehensive revision of this genus recognizing 27 species is presented here. <i>Werneria heteroloba </i>and <i>W. obtusiloba </i>are synonymized with <i>W. pinnatifida</i>, and <i>W. acerosifolia </i>is synonymized with <i>W. staticifolia</i>. Moreover, five infraspecific names and three supraspecific names are synonymized. Detailed descriptions, distribution maps, photographs of living plants (except for <i>W. cochlearis</i>), and a list of all specimens examined are provided for each accepted species. An identification key to the species and a list of exsiccatae are also given. Eight species are illustrated, two of them for the first time. The following names are lectotypified: <i>Werneria brachypappa </i>Sch. Bip., <i>W. caespitosa </i>Wedd., <i>W. calyculata </i>Turcz., <i>W. canaliculata </i>Sch. Bip., <i>W. carnulosa </i>A. Gray, <i>W. densa </i>Benth., <i>W. disticha </i>Kunth, <i>W. glaberrima </i>Phil., <i>W. glandulosa </i>Wedd., <i>W. heteroloba </i>f. <i>microcephala </i>Rockh., <i>W. mandoniana </i>Wedd. ex Klatt, <i>W. nubigena </i>Kunth, <i>W. nubigena </i>var. <i>caulescens </i>Wedd., <i>W. nubigena </i>var. <i>dombeyana </i>Wedd., <i>W. orbignyana </i>Wedd., <i>W. orbignyana </i>var. <i>breviradiata </i>A. Gray, <i>W. orbignyana </i>var. <i>longifolia </i>Rockh., <i>W. pectinata </i>Lingelsh., <i>W. plantaginifolia </i>Wedd. ex Klatt, <i>W. pygmaea </i>var. <i>caespitosa </i>Wedd., <i>W. rhizoma </i>J. Rémy, <i>W. solivifolia </i>Sch. Bip., <i>W. staticifolia </i>Sch. Bip., <i>W. staticifolia </i>var. <i>celmisioides </i>Wedd., and <i>W. villosa </i>A. Gray. The names <i>Werneria knocheae </i>Perkins, <i>W. minima </i>Walp., <i>W. minima </i>var. <i>pygmaea </i>Walp., and <i>W. stuebelii </i>Hieron. are neotypified, and an epitype is designated for <i>W. glandulosa</i>. At the supraspecific level, the name <i>Werneria </i>sect. <i>Integrifoliae </i>Rockh. is typified.

Evidence of volcanic activity in the growth rings of trees at the Tacaná volcano, Mexico–Guatemala border

Volcanic activity can have a significant effect on the growth and survival of trees. The objective of our research was to analyze the effects of the 1855–1856 eruption of the Tacaná volcano and the ashfall from the 1902 eruption of the Santa María volcano, Guatemala, on the radial growth of trees at Tacaná. Dendrochronological sampling was carried out on sites covered by Pinus hartwegii Lindl., and a ring-width chronology was built using 102 increment cores from 75 trees. The ring-width chronology shows two statistically significant suppression events. One of these events occurred from 1857 to 1868 and was potentially caused by the historic eruption of Tacaná (1855–1856). The second suppression event occurred from 1903 to 1908, during which tree growth was affected 1 year after the ashfall caused by the 1902 eruption of Santa María. The growth suppression did not have the same magnitude in all sampled trees and may be related to the thickness of the ash layer deposited around each tree. For the first time, we show that tree growth at Tacaná is reduced by ashfall from volcanic eruptions. Our results may contribute to the evaluation of risks associated with the volcanic activity of the Tacaná volcano.

INTERCAMBIO DE PLANTAS ENTRE HUERTOS Y OTROS ESPACIOS: ¿UNA ESTRATEGIA DE CONSERVACIÓN PARA EL BOSQUE MESÓFILO DE MONTAÑA DEL VOLCÁN TACANÁ, CHIAPAS, MÉXICO?

Se analiza el papel que realiza una de las prácticas de conservación en los huertos de una comunidad mame en la Reserva de Biosfera Volcán Tacaná; Chiquihuite, Unión Juárez, Chiapas. Lo anterior, se llevó a cabo mediante la recolecta e identificación de las especies presentes en veinticuatro huertos de la comunidad y entrevistas semi estructuradas sobre el espacio de origen y el uso a la especie. Con esta información se elaboró una matriz de presencia-ausencia y una red de relaciones entre espacios, y se concluyó que existe una práctica de intercambio, principalmente entre los espacios huerto-montaña y huerto-huerto. La base de este intercambio es el uso y por ello la definición local del concepto de conservación, no se explica sin este concepto. INTERCHANGE OF PLANTS BETWEEN HOME GARDENS AND OTHER SPACES: A CONSERVATION STRATEGY FOR THE CLOUD FOREST OF THE TACANÁ VOLCANO IN CHIAPAS STATE, MEXICO? This paper analyzes the role played by one of the conservation practices carried out in the home gardens of a Mame community in the Tacaná Volcano Biosphere Reserve: Chiquihuite, in the Unión Juárez municipality of Chiapas State. This analysis was conducted through collecting and identifying the species present in 24 of the home gardens of the community as well as semi-structured interviews regarding the space of origin and use of the species. Based on this information, a presence-absence matrix was developed as well as a network of relationships between spaces. It was concluded that there is a practice of interchange, mainly between home garden and mountain, and between home garden and home garden. This interchange is based on use and therefore the local definition of conservation cannot be explained without this concept.