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Grant, Jason

Nom
Grant, Jason
Affiliation principale
Fonction
Professeur.e ordinaire
Email
jason.grant@unine.ch
Identifiants
https://libra.unine.ch/handle/123456789/30709
_
0000-0002-1197-1131

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  • Publication
    Accès libre
    DE MACROCARPAEAE GRISEBACH (EX GENTIANACEIS) SPECIEBUS NOVIS XI: FIVE NEW SPECIES FROM THE ANDES OF ECUADOR AND COLOMBIA
    (2014)
    Grant, Jason 
    Five new species are described from Andean regions of Colombia and Ecuador including M. catherineae, M. cortinae, M. illuminata, M. pacifica, and M. umbellata. Macrocarpaea stenophylla is reported as a range extension from Peru to Ecuador.
  • Publication
    Accès libre
    DE MACROCARPAEAE GRISEBACH (EX GENTIANACEIS) SPECIEBUS NOVIS XII: THREE NEW SPECIES FROM THE ANDES OF PERU
    (2014)
    Grant, Jason 
    ;
    Vieu, Julien 
    Three new species from Peru, Macrocarpaea abiseo, M. felicitata, and M. huamantanga, are described and illustrated.
  • Publication
    Accès libre
    DE MACROCARPAEAE GRISEBACH (EX GENTIANACEIS) SPECIEBUS NOVIS X: A SYNOPSIS OF THE GENUS IN MONTANE ATLANTIC FORESTS OF BRAZIL
    (2011)
    Grant, Jason 
    ;
    Trunz, Vincent
    Outside of the principal distribution and major diversification of Macrocarpaea in the Andes, smaller groups of species are found in the Greater Antilles of the Caribbean, Mesoamerica, the Guayana Highlands, and montane Atlantic forests of Brazil. Here, a complete revision of the genus in the latter region is presented recognizing eight species that correspond to the entirety of Macrocarpaea sect. Tabacifoliae: M atlantica J.R. Grant & V. Trunz, sp. nov., M. dolichophylla J.R. Grant & V. Trunz, sp. nov., M. glaziovii Gilg, M. illecebrosa J.R. Grant, M. inesiae J.R. Grant & V. Trunz, sp. nov., M. obtusifolia (Griseb.) Gilg, M. orbiculata J.R. Grant & V. Trunz, sp. nov., and M. rubra Malme. These species occur primarily in humid coastal montane rainforests (Mata Atlântica), and two species also occur in campos rupestre montane savannas.
  • Publication
    Accès libre
    DE MACROCARPAEAE GRISEBACH (EX GENTIANACEIS) SPECIEBUS NOVIS IX: A SYNOPSIS OF THE GENUS IN BOLIVIA
    (2011)
    Grant, Jason 
    A synopsis of the genus Macrocarpaea in Bolivia is presented. Four species are recognized including M. bangiana Gilg, M. cinchonifolia (Gilg) Weaver, M. cochabambensis Gilg-Ben., and M. fuentesii J.R. Grant, sp. nov. These are the four southernmost species of Macrocarpaea in the Andes.
  • Publication
    Accès libre
    Andean Speciation and Vicariance in Neotropical Macrocarpaea (Gentianaceae-Helieae)
    (2009)
    Struwe, Lena
    ;
    Haag, Scott
    ;
    Heiberg, Einar
    ;
    Grant, Jason 
    The genus Macrocarpaea (Griseb.) Gilg (Gentianaceae, Helieae) is among the largest woody genera of tropical gentians, with most of its species occurring in the wet mountainous forests of the Andes. Phylogenetic and dispersal-vicariance analyses (DIVA) of 57 of the 105 currently recognized species in the genus, using two data sets from nuclear DNA (ITS and 5S-NTS sequences) and morphology, show a single origin of the Andean species from an ancestral distribution that includes southeastern Brazil. Within the Andes, species divide into two major clades: (1) northern species from the cordilleras of northern Ecuador, Colombia, and Venezuela; and (2) southern species of the Andean Amotape–Huancabamba Zone in Ecuador and Peru, as well as the Andes of central and southern Peru and Bolivia. The Amotape–Huancabamba Zone is supported as the ancestral area for Macrocarpaea within the Andes. There are repeated speciation patterns within the Andes, and three Mesoamerican species derive from the northern clade, as is the single sampled species from the Guayana Shield. The position of the subclade of the three Caribbean species is less certain, but it currently nests among Andean species. An Atlantic coastal Brazilian clade is placed as sister group to all other Macrocarpaea, providing further support for an ancestral refuge in southeastern Brazil for the Helieae. The biogeographic analysis showed that local speciation is more common than long-distance dispersal, and allopatric speciation is more common than sympatric speciation. Using detailed, georeferenced herbarium collection data, patterns in environmental characteristics between clades and sister species were analyzed with Spatial Evolutionary and Ecological Vicariance Analysis (SEEVA), utilizing geographic information system (GIS) and statistical methods. Sister clades and taxa were evaluated for statistical significance in variables such as annual rainfall and temperature, elevation, temperature and rainfall seasonality, geological bedrock age, and soil type to evaluate ecological vicariance between sister groups. The results indicate that there are no general patterns for each variable, but that there are many significant divergences in ecological niches between both larger sister groups and sister species, and ecological niche conservation was also observed when subsequent nodes in the phylogeny were compared.
  • Publication
    Accès libre
    DE MACROCARPAEAE GRISEBACH (EX GENTIANACEIS) SPECIEBUS NOVIS VIII: FOUR NEW SPECIES FROM ECUADOR
    (2008)
    Grant, Jason 
    Two new species, Macrocarpaea claireae and M. quizhpei (Gentianaceae: Helieae), are described from the Huancabamba region of southern Ecuador. Macrocarpaea claireae occurs around Valladolid, adjacent to P. N. Podocarpus, and M. quizhpei occurs in the Nangaritza watershed. M. claireae is closely related to M. pringleana and M. sodiroana, yet differs notably in its glaucous-green, campanulate-urceolate calyx. Macrocarpaea quizhpei has affinities to M. dies-viridis, but differs in having a large, diffusely branched, open thyrse to 1.3 m high.
  • Publication
    Accès libre
    DE MACROCARPAEAE GRISEBACH (EX GENTIANACEIS) SPECIEBUS NOVIS VII: FOUR NEW SPECIES AND TWO NATURAL HYBRIDS
    (2007)
    Grant, Jason 
    Four new species, Macrocarpaea dies-viridis (Ecuador), M. luctans (Ecuador, Peru), M. lucubrans (Panama), and M. opulenta (Ecuador), and two natural hybrids, M. × acuminata (Costa Rica) and M. × mattii (Ecuador), are described. Macrocarpaea × acuminata Weaver (pro sp.) is recognized as a natural hybrid between M. subcaudata and M. valerii, rather than as a distinct species, and M. × mattii is described here as a natural hybrid between M. noctiluca and M. subsessilis. The average number of seeds per capsule of M. dies-viridis is reported. With 10,400–11,000 seeds per capsule, the is first report in the genus.
  • Publication
    Accès libre
    Wood anatomy of Gentianaceae, tribe Helieae, in relation to ecology, habit, systematics, and sample diameter
    (2005)
    Carlquist, Sherwin
    ;
    Grant, Jason 
    Twenty collections representing one species each of Symbolanthus and Tachia, and 17 species of Macrocarpaea were studied by means of light microscopy and scanning electron microscopy (SEM). Wood details show that the three genera form a coherent group; Tachia differs from the others in only a few minor characters. Because the species studied form a natural group, wood variations within Helieae offer the basis for correlations and interpretations with respect to habit and ecology. Diameter of stems studied proves to be an important variable that must be taken into account. Correlations with stem diameter include wider vessels in outer wood of wider samples. This would correspond to deeper penetration of reliable water tables by roots of helioid trees or large shrubs. Ray height decreases with increase in stem diameter, an indication of paedomorphosis. Rays of all species are paedomorphic in histology by virtue of relative paucity or even absence of procumbent cells in multiseriate rays. Pseusoscalariform lateral wall pitting of vessels is also a feature characteristic of paedomorphosis. The assemblage of paedomorphic features correlates well with the conclusion, reached by authors who used cladistic methods, that Gentianaceae other than Gentianeae are derived from suffrutescent prennials. The Mesomorphy Ratio, which incorporates three vessel features, correlates with leaf length and with stem diameter. All Helieae are mesophytic, but to various degrees. Septate fiber-tracheids, where present, are typically near vessels and form a substitute for or an addendum to vasicentric axial parenchyma as a mechanism for photosynthate storage. Vestured pits occur on lateral wall pits of vessels of all Helieae, but not on the fibertracheids. Vestured pits show diversity within Macrocarpaea, a feature of possible systematic significance.
  • Publication
    Accès libre
    DE MACROCARPAEAE GRISEBACH (EX GENTIANACEIS) SPECIEBUS NOVIS V: TWENTY-THREE NEW SPECIES LARGELY FROM PERU, AND TYPIFICATION OF ALL SPECIES IN THE GENUS
    (2004)
    Grant, Jason 
    In preparation for a monograph of Macrocarpaea (Gentianaceae: Helieae), 23 new species are here described and illustrated: 1 from Colombia (M. biremis), 3 from Ecuador (M. elix, M. gattaca, and M. pringleana), and 19 from Peru (M. canoëfolia, M. dillonii, M. ericii, M. fortisiana, M. innarrabilis, M. jalca, M. kayakifolia, M. kuelap, M. kuepferiana, M. luya, M. normae, M. obnubilata, M. ostentans, M. pajonalis, M. robin-fosteri, M. tabula-fluctivagifolia, M. tahuantinsuyuana, M. wallnoeferi, and M. weigendiorum). A list of all names originally described in, or transferred to, Macrocarpaea as of year 2002 is presented. Lectotypes are selected for 12 taxa as follows: Lisianthus obtusifolius var. constrictus Griseb., Macrocarpaea bangiana Gilg, M. bogotana Gilg, M. calophylla Gilg, M. chlorantha Gilg, M. cochabambensis Gilg-Ben., M. glaziovii Gilg, M. hartii Krug & Urb., M. micrantha Gilg, M. pachyphylla Gilg, M. polyantha Gilg, and M. rubra Malme. A neotype is selected for M. duquei Gilg-Ben., and M. weberbaueri Gilg is excluded from use.
  • Publication
    Accès libre
    DE MACROCARPAEAE GRISEBACH (EX GENTIANACEIS) SPECIEBUS NOVIS III: SIX NEW SPECIES OF MOON-GENTIANS (MACROCARPAEA, GENTIANACEAE: HELIEAE) FROM PARQUE NACIONAL PODOCARPUS, ECUADOR
    (2003)
    Grant, Jason 
    ;
    Struwe, Lena
    In preparation for the Flora Neotropica monograph of Macrocarpaea (Gentianaceae: Helieae) and recent fieldwork in Ecuador, six new species have been identified and are here described from Parque Nacional Podocarpus and its surrounding areas in Loja and Zamora-Chinchipe provinces. These are Macrocarpaea apparata, M. bubops, M. jensii, M. lenae, M. luna-gentiana, and M. noctiluca. For each new species, descriptions, illustrations, and ecological information are provided. The neotropical montane genus Macrocarpaea has among the highest biodiversity in Ecuador with over 30 species present. The name “moon-gentian” or “genciana de luna” is coined as the common name for the genus Macrocarpaea.