Notas sobre el género Phytolacca (Phytolaccaceae) en México
The genus Phytolacca is a taxonomically difficult one and its classificatory arrangement is pending a thorough reappraisal. A study of more than 1100 collection numbers shows the existence in Mexico of five more or less reasonably distinct entities: P. americana L., P. icosandra L., P. rivinoides Ku...
| Hauptverfasser: | , |
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| Format: | Online |
| Sprache: | spa |
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Instituto de Ecología, A.C.
2000
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| Online Zugang: | https://abm.ojs.inecol.mx/index.php/abm/article/view/862 |
| _version_ | 1799771227059912704 |
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| author | Rzedowski, Jerzy Calderón de Rzedowski, Graciela |
| author_facet | Rzedowski, Jerzy Calderón de Rzedowski, Graciela |
| author_sort | Rzedowski, Jerzy |
| collection | ABM |
| description | The genus Phytolacca is a taxonomically difficult one and its classificatory arrangement is pending a thorough reappraisal. A study of more than 1100 collection numbers shows the existence in Mexico of five more or less reasonably distinct entities: P. americana L., P. icosandra L., P. rivinoides Kunth & Bouché, P. rugosa Braun & Bouché and P. thyrsiflora Fenzl ex J. A. Schmidt. Although several authors expressed their doubts concerning the presence of P. americana in Mexico, the study of abundant materials obtained in last decades reveals that this species extends its area along the moister places of the Sierra Madre Oriental, from Nuevo León and Tamaulipas to northern Oaxaca. Its Mexican populations are morphologically more variable than those of eastern United States and in such circumstances it is believed that the species may have originated in Mexico and subsequently colonized ecologically similar territories situated to the north. P. heterotepala H. Walt., distinguished on the basis of slightly zygomorphic perianths, only seems to comprehend cases of floral anomalies in individuals of P. icosandra and P. rugosa. P. icosandra and P. octandra L. are usually differentiated from each other in the number of stamens and in the length of the inflorescence. However, in central and southern Mexico numerous populations exist, in which plants do not adjust to this separation. Thus, in the expectation of a detailed study of this situation, only one taxon is recognized. Although P. rugosa differs from the remaining regional members of Phytolacca in its apically free carpels, its taxonomic situation and circumscription is not clear. In Mexico within this complex two groups of plants can be separated on the basis of their morphological and ecological affinities, one of them being much more similar to P. icosandra than the other, possibly under stronger genetic influence of the latter. Among the examined material several specimens show the trend toward inflorescence branching in its lower part. Three of these specimens do not differ in other characters from P. americana, P. rivinoides and P. rugosa, respectively, and are interpreted as sporadical variants of these species. Several possibly belong to P. thyrsiflora Fenzl ex J. A. Schmidt, an essentially South American species, the cirumscription of which remains to be defined. In terms of conclusions it can be proposed that future approximations to the taxonomy of Phytolacca reduce their dependence from the computation of stamen-numbers and incorporate more emphasis on the aspect of ecological affinities of the plants. More attention is also recommended to the possibility of incidence of floral anomalies and in view of the importance of birds as dispersers of Phytolacca seeds, the genetic consequences of long and medium-distance dispersal are to be considered. |
| format | Online |
| id | oai:oai.abm.ojs.inecol.mx:article-862 |
| institution | Acta Botanica Mexicana |
| language | spa |
| publishDate | 2000 |
| publisher | Instituto de Ecología, A.C. |
| record_format | ojs |
| spelling | oai:oai.abm.ojs.inecol.mx:article-8622022-12-24T05:14:52Z Notas sobre el género Phytolacca (Phytolaccaceae) en México Rzedowski, Jerzy Calderón de Rzedowski, Graciela The genus Phytolacca is a taxonomically difficult one and its classificatory arrangement is pending a thorough reappraisal. A study of more than 1100 collection numbers shows the existence in Mexico of five more or less reasonably distinct entities: P. americana L., P. icosandra L., P. rivinoides Kunth & Bouché, P. rugosa Braun & Bouché and P. thyrsiflora Fenzl ex J. A. Schmidt. Although several authors expressed their doubts concerning the presence of P. americana in Mexico, the study of abundant materials obtained in last decades reveals that this species extends its area along the moister places of the Sierra Madre Oriental, from Nuevo León and Tamaulipas to northern Oaxaca. Its Mexican populations are morphologically more variable than those of eastern United States and in such circumstances it is believed that the species may have originated in Mexico and subsequently colonized ecologically similar territories situated to the north. P. heterotepala H. Walt., distinguished on the basis of slightly zygomorphic perianths, only seems to comprehend cases of floral anomalies in individuals of P. icosandra and P. rugosa. P. icosandra and P. octandra L. are usually differentiated from each other in the number of stamens and in the length of the inflorescence. However, in central and southern Mexico numerous populations exist, in which plants do not adjust to this separation. Thus, in the expectation of a detailed study of this situation, only one taxon is recognized. Although P. rugosa differs from the remaining regional members of Phytolacca in its apically free carpels, its taxonomic situation and circumscription is not clear. In Mexico within this complex two groups of plants can be separated on the basis of their morphological and ecological affinities, one of them being much more similar to P. icosandra than the other, possibly under stronger genetic influence of the latter. Among the examined material several specimens show the trend toward inflorescence branching in its lower part. Three of these specimens do not differ in other characters from P. americana, P. rivinoides and P. rugosa, respectively, and are interpreted as sporadical variants of these species. Several possibly belong to P. thyrsiflora Fenzl ex J. A. Schmidt, an essentially South American species, the cirumscription of which remains to be defined. In terms of conclusions it can be proposed that future approximations to the taxonomy of Phytolacca reduce their dependence from the computation of stamen-numbers and incorporate more emphasis on the aspect of ecological affinities of the plants. More attention is also recommended to the possibility of incidence of floral anomalies and in view of the importance of birds as dispersers of Phytolacca seeds, the genetic consequences of long and medium-distance dispersal are to be considered. El género Phytolacca es de los taxonómicamente difíciles y su arreglo clasificatorio está pendiente de una cuidadosa revaluación. El examen de más de 1100 números de colecta revela la existencia en nuestro país de cinco entidades más o menos razonablemente distintas: P. americana L., P. icosandra L., P. rivinoides Kunth & Bouché, P. rugosa Braun & Bouché y P. thyrsiflora Fenzl ex A. J. Schmidt. Aunque varios autores dudaron acerca de la presencia de P. americana más al sur de la porción oriental de los Estados Unidos, el estudio de abundantes materiales obtenidos en las últimas décadas, señala que esta especie extiende su área de distribución a lo largo de los parajes más húmedos de la Sierra Madre Oriental, desde Nuevo León y Tamaulipas hasta el norte de Oaxaca. Sus poblaciones mexicanas muestran mayor variabilidad morfológica que la observada en el oriente estadounidense y en función de tal circunstancia se piensa que la especie pudo haberse originado en este país y colonizado con posterioridad territorios ecológicamente similares, ubicados más al norte. P. heterotepala H. Walt., diferenciada a base del perianto ligeramente zigomórfico, al parecer sólo representa casos de anomalía floral en individuos de P. icosandra y de P. rugosa. P. icosandra y P. octandra L. se han estado distinguiendo entre sí en función del diferente número de estambres y del largo de la inflorescencia. En el centro y sur de México, sin embargo, existen muchas poblaciones que no pueden asignarse claramente a ninguna de estas dos especies y, en expectativa de un estudio detallado que defina esta situación, se considera apropiado reconocer un solo taxon. Aunque P. rugosa diverge de los demás representantes regionales de Phytolacca en sus carpelos libres en el extremo apical, su ubicación y circunscripción taxonómica no es clara. En México se pueden separar dos conjuntos morfológica y ecológicamente algo diferentes, uno de ellos mucho más similar a P. icosandra que el otro y posiblemente afectado por una mayor influencia genética de esta última especie. Entre los materiales revisados se encontraron varios ejemplares en los que se pone de manifiesto la tendencia hacia la ramificación de la inflorescencia en sus porciones inferiores. Tres de estos individuos no difieren en otros caracteres de P. americana, P. rivinoides y P. rugosa, respectivamente y se interpretan como variantes esporádicas de tales especies. Algunos posiblemente pertenecen a P. thyrsiflora Fenzl ex J. A. Schmidt, especie de distribución esencialmente sudamericana, pero cuya circunscripción está todavía por definirse. A título de conclusiones, se propone que las futuras aproximaciones a la taxonomía de Phytolacca reduzcan su dependencia del cómputo del número de los estambres e incorporen con más énfasis el aspecto de las afinidades ecológicas de las plantas. Se recomienda asimismo prestar debida atención a la posibilidad de la incidencia de anomalías florales y, en función de la importancia de las aves como dispersores de sus semillas, se sugiere tomar en cuenta las posibles consecuencias genéticas de la propagación a mediana y larga distancia. Instituto de Ecología, A.C. 2000-10-01 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion artículo evaluado por pares application/pdf https://abm.ojs.inecol.mx/index.php/abm/article/view/862 10.21829/abm53.2000.862 Acta Botanica Mexicana; No. 53 (2000); 49-66 Acta Botanica Mexicana; Núm. 53 (2000); 49-66 2448-7589 0187-7151 spa https://abm.ojs.inecol.mx/index.php/abm/article/view/862/1028 Derechos de autor 2016 Acta Botanica Mexicana https://creativecommons.org/licenses/by-nc/4.0 |
| spellingShingle | Rzedowski, Jerzy Calderón de Rzedowski, Graciela Notas sobre el género Phytolacca (Phytolaccaceae) en México |
| title | Notas sobre el género Phytolacca (Phytolaccaceae) en México |
| title_full | Notas sobre el género Phytolacca (Phytolaccaceae) en México |
| title_fullStr | Notas sobre el género Phytolacca (Phytolaccaceae) en México |
| title_full_unstemmed | Notas sobre el género Phytolacca (Phytolaccaceae) en México |
| title_short | Notas sobre el género Phytolacca (Phytolaccaceae) en México |
| title_sort | notas sobre el género phytolacca (phytolaccaceae) en méxico |
| url | https://abm.ojs.inecol.mx/index.php/abm/article/view/862 |
| work_keys_str_mv | AT rzedowskijerzy notassobreelgenerophytolaccaphytolaccaceaeenmexico AT calderonderzedowskigraciela notassobreelgenerophytolaccaphytolaccaceaeenmexico |
