Phylogeny of Agavaceae Based on ITS rDNA Sequence Variation

Abstract

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.Several systems of classification have been proposed for the family Agavaceae. A distinctive bimodal karyotype and similarities of fruits and seeds strongly support close relationships among Yucca, Hesperaloe, Beschorneria, Furcraea, Agave, Manfreda, Polianthes, Prochnyanthes, and perhaps Hosta. However, Dasylirion, Beaucarnea, Nolina, Calibanus, Dracaena, and Sansevieria differ in so many cytological and morphological features that many have concluded they should be excluded from Agavaceae and separated into two families, Nolinaceae and Dracaenaceae. Chloroplast DNA restriction site data support these separations and indicate that Nolinaceae and Dracaenaceae are very close to Convallariaceae (Maianthemum, Convallaria, Aspidistra, Liriope, etc.). In this paper we report the results of an ITS rDNA sequencing study of 40 taxa in Agavaceae sensu lato and related groups in the order Asparagales. Sequence alignments were optimized using the Consistency Index, Retention Index, and Rescaled Consistency Index to find the alignment that exhibited the least amount of homoplasy. The results of our study are congruent with the conclusions drawn from cytological, immunological, cpDNA, and rbcL studies, which support a narrow interpretation of Agavaceae and a close relationship among Convallariaceae, Dracaenaceae, and Nolinaceae. In addition, the ITS sequence data provide evidence for some interesting relationships within these families.

Molecular phylogenetics and morphology of Beaucarnea (Ruscaceae) as distinct from Nolina, and the submersion of Calibanus into Beaucarnea

“…We included ten species and two putative species of Beaucarnea, two species of Calibanus, five species of Dasylirion Zucc., and six species of Nolina. We included samples of Dasylirion because it is closely related to the other three genera (Hernández, 1993a;Eguiarte & al., 1994;, 1996. We show that Beaucarnea is a well-supported entity, and confirm its distinctness from Nolina.…”

“…S1-S2). Our results suggesting the mutual monophyly of these genera are therefore in agreement with previous studies based on molecular data that included more than one species of Beaucarnea and Nolina (Eguiarte & al., 1994;, 1996. Other phylogenetic studies, which considered Beaucarnea a synonym of Nolina, recovered Nolina as the sister taxon to either Calibanus or Dasylirion Chase & al., 1995Yamashita & Tamura, 2000).…”

A Chloroplast Phylogeny of Agavaceae subfamily Chlorogaloideae: Implications for the Tempo of Evolution on Serpentine Soils

“…The inclusion of Chlorogalum and Camassia in Agavaceae was later supported by several phylogenetic analyses (Bogler and Simpson 1996;Pfosser and Speta 1999;Bogler et al 2006;Good-Avila et al 2006;Smith et al 2008;Seberg et al 2012). In all cases, the position of these genera within Agavaceae was unresolved.…”

“…data). In order to evaluate the monophyly of Chlorogaloideae and determine its position within Agavaceae, we selected outgroups from Agavaceae s. s. to represent major clades found in prior studies (Bogler and Simpson 1995;Bogler and Simpson 1996;Bogler et al 2006;Smith et al 2008). We included one of five species of Hesperaloe Engelm.…”

“…Of the remaining genera of Chlorogaloideae, Hastingsia has been sampled in only one phylogenetic study, which was focused on relationships within Camassia (Fishbein et al 2010), and Schoenolirion has not been sampled as yet. Based on recent phylogenetic and taxonomic work, these genera have been placed in Agavaceae (Bogler and Simpson 1996;Bogler et al 2006;Smith et al 2008;Fishbein et al 2010), or alternatively within subfamily Agavoideae in a broad Asparagaceae (APG 2009;Chase et al 2009). For clarity and simplicity, we maintain recognition of Agavaceae in this paper.…”