Plant Ecology and Evolution 150(1): 76-86, doi: 10.5091/plecevo.2017.1276
Morphometric analysis of Milla biflora (Asparagaceae: Brodieaoideae), with an identification key for Milla
Jorge Gutiérrez, Teresa Terrazas‡, Isolda Luna-Vega‡ Universidad Nacional Autónoma de México, Mexico City, Mexico
© Botanic Garden Meise and Royal Botanical Society of Belgium. all rights reserved Citation:
Gutiérrez J, Terrazas T, Luna-Vega I (2017) Morphometric analysis of Milla biflora (Asparagaceae: Brodieaoideae), with an identification key for Milla. Plant Ecology and Evolution 150(1): 76-86. https://doi.org/10.5091/plecevo.2017.1276 |  |
Abstract
Background and aims – The taxonomical delimitation of Milla biflora has been controversial and is possibly associated with the high morphological variation of this taxon. The aims of this study were to find morphological characters that allow to distinguish groups among M. biflora and to analyse the morphological variation, with the purpose of generating an identification key.
Methods – A multivariate analysis was based 24 quantitative characters of nine species of the genus Milla. Nine morphometric characters that had the highest loadings in the multivariate analysis plus 18 qualitative characters were used to run a cluster analysis.
Key results – Discriminant analysis showed that the quantitative characters selected by the canonical discriminant analysis do not allow distinguishing all the species studied. Only the combination of qualitative and quantitative characters favours the separation of the species through the cluster analysis. Cluster analysis allowed the recognition of 35 groups with a dissimilarity value > 0.80. Twenty-six morphotypes differ from the other Milla species, previously recognized, in at least one character. An identification key for Milla, based on the diagnostic characters retrieved, distinguishes eight Milla species, as well as 26 morphotypes of M. biflora s. str. Milla biflora s. str. can be identified by its fistulose leaves, a pedicel (1.5–3 cm long) lacking an evident articulation, white flowers that are open during the day and night, three tepal nerves, elliptic outer tepals, narrowly elliptic inner tepals with widely attenuated base, filaments less than 1 mm long and yellow anthers. It is geographically located south to the Mexican Plateau and in part of the Trans-Mexican Volcanic Belt, where the type locality is situated.
Methods – A multivariate analysis was based 24 quantitative characters of nine species of the genus Milla. Nine morphometric characters that had the highest loadings in the multivariate analysis plus 18 qualitative characters were used to run a cluster analysis.
Key results – Discriminant analysis showed that the quantitative characters selected by the canonical discriminant analysis do not allow distinguishing all the species studied. Only the combination of qualitative and quantitative characters favours the separation of the species through the cluster analysis. Cluster analysis allowed the recognition of 35 groups with a dissimilarity value > 0.80. Twenty-six morphotypes differ from the other Milla species, previously recognized, in at least one character. An identification key for Milla, based on the diagnostic characters retrieved, distinguishes eight Milla species, as well as 26 morphotypes of M. biflora s. str. Milla biflora s. str. can be identified by its fistulose leaves, a pedicel (1.5–3 cm long) lacking an evident articulation, white flowers that are open during the day and night, three tepal nerves, elliptic outer tepals, narrowly elliptic inner tepals with widely attenuated base, filaments less than 1 mm long and yellow anthers. It is geographically located south to the Mexican Plateau and in part of the Trans-Mexican Volcanic Belt, where the type locality is situated.
Keywords
ASPARAGALES; MILLA COMPLEX; MULTIVARIATE ANALYSIS; TAXONOMY; TRANS-MEXICAN VOLCANIC BELT