Bryological and Lichenological Section/ABLS
De Luna, Efrain , Gomez, Gilberto .
Morphometric distinction and geographic variation of Braunia secunda and Braunia andrieuxii in US, Mexico and Guatemala.
Previous cladistic analyses revealed that Braunia secunda and B. andriuxii are two separate lineages and therefore valid species. However, both have commonly been considered synonyms due to striking morphological similarities. This study was carried out to evaluate which characters can be used to distinguish these two species based on specimens collected in the US, Mexico and Guatemala. A total of 180 specimens of B. andrieuxii and 112 of B. secunda were examined for morphometric analyses. Digital images of capsules, entire leaves, and groups of leaf cells were used to extract 31 linear measurements. Observations were grouped into three and four geographic regions for each species to compare levels of variation within and among species with univariate and multivariate analyses of variance. According to the Coefficient of Variation, the leaves, seta and capsules are extremely variable, but no geographic pattern is evident. Univariate tests confirm that most of the variables are similar among regions, except the length of the revolute leaf margin and apical and medial leaf cells, which are significantly different in both species (ANOVA and MRT). Two separate canonical variates analyses on eight variables of leaf cells and seven variables of vegetative leaves identified that the Mahalanobis distance is significant between the two species. These ordination methods also revealed that the revolute leaf margin and apical and medial leaf cells contribute most to the distinction between species. Based on these analyses, a key is developed to help in the correct identification of B. andrieuxii and B. secunda.
1 - Instituto de Ecologia AC, Sistematica Vegetal, Xalapa, Veracruz, 91000, Mexico
2 - Universidad de Ciencias y artes de Chiapas, Escuela de Biologia, Tuxtla Gutierrez, Chiapas,
Presentation Type: Paper
Location: Ballroom 3 (Cliff Lodge)
Date: Tuesday, August 3rd, 2004
Time: 2:30 PM