Néstor D. Bayón

Cladistic Analysis of the Briza Complex (Poaceae, Poeae)

The Briza complex comprises 23 species from South America, Mesoamerica and Europe. They constitute a monophyletic group because of the tendency of the spikelets to be dorsiventrally compressed. A cladistic analysis of the complex was performed using 32 characters from morphology. The terminal taxa were the species of the genera Briza, Calotheca, Microbriza, Poidium and Rhomboelytrum. Dactylis and Arrhenatherum were chosen to root the cladograms. Results of the cladistic analysis of the complex provide support for the ideas of Nicora and Rugolo (1981, Darwiniana 23(1), 279–309): Briza, Calotheca, Microbriza, Poidium and Rhomboelytrum are supported as monophyletic groups. Within Briza, only the Chascolytrum group appears monophyletic, while the Briza and Uniolae groups are paraphyletic. Poidium ambiguum, sometimes placed in Poa, is considered here as Poidium.

New circumscription of the genus Gamochaeta (Asteraceae, Gnaphalieae) inferred from nuclear and plastid DNA sequences

Gamochaeta (tribe Gnaphalieae, Asteraceae) is composed of ca. 60 species primarily distributed in tropical and subtropical America. Within the tribe Gnaphalieae, the genus is characterized by capitula arranged in spikes or head-like clusters, few hermaphroditic central florets, truncate style branches with apical sweeping trichomes, pappus bristles connate at the base into a ring falling as a unit, and achenes with globose twin trichomes. Previous molecular phylogenetic studies have suggested the paraphyly of the genus, but have not provided a basis for redefining generic limits due to incomplete taxon sampling. To address this problem, DNA sequences from the plastid (trnL-F) and nuclear (ETS and ITS) genomes were analyzed from a broad taxon sample representing the full range of morphological variation known in the genus. Our results affirm that Gamochaeta is paraphyletic as presently circumscribed. Two clades can be recognized: one clade that includes the majority of the species currently assigned to Gamochaeta and a second clade that includes Gamochaetopsis, Stuckertiella and seven species of Gamochaeta. We present here a new circumscription of Gamochaeta, including two new combinations, Gamochaeta alpina and Gamochaeta peregrina, and the resurrection of Gamochaeta capitata. Our results also show Omalotheca supina, O. norvegica and O. sylvatica, which were placed by some authors in Gamochaeta or in Gnaphalium, form a monophyletic group distantly related to both genera.

Revisión taxonómica del género Gamochaeta Wedd. (Gnaphalieae, Asteraceae) en Chile

Este trabajo comprende la revision de 24 especies de Gamochaeta para Chile, G. aliena, G. alpina, G. americana, G. andina, G. axillaris, G. chamissonis, G. depilata, G. deserticola, G. falcata, G. filaginea, G. humilis, G. longipedicellata, G. neuquensis, G. nivalis, G. oligantha, G. procumbens, G. ramosa, G. serpyllifolia, G. simplicicaulis, G. spiciformis, G. stachydifolia, G. subfalcata, G. valparadisea y G. villarroelii. Se incluye una clave para identificarlas y para cada una de las especies se brinda descripcion, ilustracion, fenologia, distribucion geografica y habitat, mapa de distribucion, material adicional examinado y afinidades taxonomicas. Sobre la base del estudio de los materiales tipo, se establecen los siguientes nuevos sinonimos: Gamochaeta foliosa con G. spiciformis; G. monticola con G. oligantha; Gnaphalium petraeum con Gamochaeta andina; G. suffruticosa con G. chamissonis; Gnaphalium bellidifolium, Gamochaeta berteroana con G. filaginea; Gnaphalium agreste con Gamochaeta stachydifolia; y se propone el nuevo nombre Gamochaeta ramosa S.E. Freire, N. Bayon & C.M. Baeza parar Gnaphalium ramosum Phil. (1864) non Lam. (1779) nec Sch. Bip. (1845). Se designan lectotipos para las siguientes especies: Gnaphalium andinum, G. berteroanum, G. suffruticosum y G. villarroelii.

Revision of the genus Pseudognaphalium (Asteraceae, Gnaphalieae) in Chile

El genero Pseudognaphalium, con cerca de 90 especies de distribucion cosmopolita, es uno de los generos de la tribu Gnaphalieae con mayor numero de especies, principalmente distribuidas en America del Sur, Central y del Norte, aunque algunas tambien estan presentes en Asia y Africa. Este trabajo comprende la revision de 12 especies de Pseudognaphalium para Chile, P. aldunateoides, P. cabrerae, P. cheiranthifolium, P. cymatoides, P. gayanum, P. lacteum, P. landbeckii, P. munoziae, P. psilophyllum, P. remyanum, P. tarapacanum y P. viravira. Se incluye una clave para identificarlas y para cada una de las especies se brinda descripcion, ilustracion, fenologia, distribucion geografica y habitat, mapa de distribucion, material adicional examinado y afinidades taxonomicas. Sobre la base del estudio de los materiales tipo, se establecen los siguientes nuevos sinonimos: Gnaphalium diminutivum, Pseudognaphalium perpusillum, con P. aldunateoides; G. canum, G. ulophyllum, P. moelleri con P. cymatoides; P. heterophyllum, P. heterotrichum, G. pseudohelichrysum, P. robustum, con P. gayanum; P. glandulosum con P. psilophyllum; G. longifolium, G. subnudum, P. andicola, P. coquimbense, P. illapelinum, P. montevidense, P. pratense, con P. viravira; se designan lectotipos para las siguientes especies: Gnaphalium acutifolium, G. araucanum, G. argyrolepis, G. canum, G. cymatoides, G. glandulosum, G. heterophyllum, G. illapelinum, G. lacteum, G. landbeckii, G. moelleri, G. ramosum, G. remyanum, G. subnudum, G. tarapacanum, G. ulophyllum, G. viravira y se designa el neotipo para G. psilophyllum.

Taxonomic Studies in Pseudognaphalium Kirp. (Asteraceae, Gnaphalieae) from Peru

Abstract An account of the nine species of Pseudognaphalium occurring in Peru is provided, i.e. P. cheiranthifolium, P. dysodes, P. elegans, P. gaudichaudianum, P. lacteum, P. lanuginosum, P. luteoalbum, P. psilophyllum, and P. viravira. A number of species are placed in synonymy: Gnaphalium ecuadorense, G. ecuadorense var. boliviense, andPseudognaphalium pellitum are synonymized under P. cheiranthifolium; Gnaphalium imbaburense, G. jelskii, G. peruvianum, G. sodiroi, and Pseudognaphalium cabrerae are synonymized under P. gaudichaudianum; Gnaphalium humillimum and Pseudognaphalium dombeyanum are synonymized under P. dysodes; Gnaphalium helichrysoides and Pseudognaphalium melanosphaeroides are synonymized under P. lanuginosum; and Gnaphalium polium is synonymized under Pseudognaphalium viravira. Lectotypes are designated for Gnaphalium dombeyanum, G. elegans, G. gaudichaudianum, G. gaudichaudianum var. subrufescens, G. helichrysoides, G. jelskii, G. luteoalbum var. pallidum, G. multiceps, G. poeppigianum, and G. sodiroi. Descriptions, notes on habitat and phenology, distribution maps, full specimen citations for all taxa treated, an identification key, as well as line drawings of four of the nine species, are provided.

Lectotipificaciones en Amaranthaceae de la Flora Argentina

Lectotypifications in Amaranthaceae for Flora Argentina. Lectotypes are designated for 36 species and 22 infraspecific taxa of Amaranthaceae for Flora Argentina which belong to the currently accepted genera Alternanthera, Blutaparon, Chamissoa, Froelichia, Hebanthe, and Pfaffia. Of all the lectotypifications, 20 are second step lectotypifications.

Pseudognaphalium munoziae (Gnaphalieae, Asteraceae): A new South American species from Chile

Pseudognaphalium is a large genus with about 90 species distributed worldwide, but with most species in America, and some in Asia, and Africa. A new species, P. munoziae , from the north of Chile (Parinacota and Iquique provinces), is described and illustrated. Pseudognaphalium munoziae is similar to P. glandulosum but it is principally distinguished by its rosulate basal leaves which are longer than the upper, all of which are apically acute to subobtuse. A key to the species of dwarf Pseudognaphalium occurring in Chile is provided along with a map of their distribution.

A New Species of Amaranthus (Amaranthaceae) from Salta, Argentina

Abstract.  Amaranthus pedersenianus N. Bayón & C. Peláez (Amaranthaceae) is a new Argentinian species of Amaranthus L. subg. Albersia (Kunth) Gren. & Godr. and is described and illustrated from the province of Salta. It is found in Andean puna and prepuna in both Salta and Jujuy provinces at altitudes between 2800 and 3775 m. Amaranthus pedersenianus is similar to A. cardenasianus Hunz., A. hunzikeri N. Bayón, A. kloosianus Hunz., A. squamulatus (Andersson) B. L. Rob., and A. urceolatus Benth. by its urceolate pistillate flowers with five sepals. The new taxon differs by its ascendant or erect habit, height of 5–20 cm, presence of leafless, short terminal inflorescences, flowers with usually four or five stamens, and dehiscent fruits.

Amaranthus hunzikeri (Amaranthaceae), a New Species from Northwestern Argentina

ABSTRACT Amaranthus hunzikeri N. Bayón (Amaranthaceae), a new Argentinian species of subgenus Albersia (Kunth) Grenier & Godron from the Andes Mountains at altitudes above 3200 m, is described and illustrated. It resembles A. cardenasianus Hunziker, A. squamulatus (Andersson) B. L. Robinson, and A. urceolatus Bentham, but it differs by the prostrate or decumbent habit, spatulate leaves, and staminate flowers with three to five sepals. A key to the species in Amaranthus L. sect. Pyxidium Moquin-Tandon is included.