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Abstract Detail


Systematics Section / ASPT

Castro-Castro, Arturo [1], Rodriguez, Aaron [2].

Principal Component Analysis of morphological variation in Prochnyanthes (Agavaceae).

Prochnyanthes S. Watson is a genus endemic to Mexico. It grows along the Trans-Mexican Volcanic Belt and the Sierra Madre Occidental in the states of Aguascalientes, Durango, Guanajuato, Jalisco, Michoacán, Nayarit, Querétaro and Zacatecas. Three species of Prochnyanthes have been described: P. mexicana P. bulliana and P. viridescens based on differences in pedicel length and the size and color of the perianth. However, species recognition can be difficult and most botanists accept only P. mexicana. The purpose of this research was to test the utility of morphological variation in the circumscription of the taxa. Data were collected for 29 morphological characters in 544 individuals of 19 populations. Principal Component Analyis was carried out in order to determine the patterns of variation in Prochnyanthes. The results show that 55.6% of the total variation is expressed along the first three Principal Components (PC). The PC I accumulated the 38.5% of the variation. All associated characters included had positive values except the ratio length/width of the perianth. In other words, individuals with longer and wider measurements had campanulate perianths while individuals with smaller structures had tubular perianths. The PC I showed two morphological types which represented the two extremes of a clinal variation in the group because the values of PC axes I and II did not separate the two groups. Similarly, PC axes II and III did not discriminate any phenotype. In conclusion, pedicel length and the size of the perianth lack any taxonomic value and therefore we only recognize P. mexicana in the genus.


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1 - Universidad de Guadalajara, Botnica y Zoologa, Las Agujas, Nextipac, Apartado Postal 139, Zapopan, Jalisco, 45101, Mexico
2 - Departamento De Botanica Y Zoologia, Apartado Postal 139, Zapopan, 45101, Mexico

Keywords:
Prochnyanthes
Agavaceae
Principal components.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P59060
Abstract ID:1046


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