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

Abstract

Despite the economic importance and longstanding worldwide commercialization of representatives of the Beaucarnea lineage, it remains poorly known systematically. One of the main systematic problems is lack of certainty regarding the validity of the genus itself. Some authors consider Beaucarnea a synonym of its close relative Nolina, whereas others consider Beaucarnea a distinct genus. In addition to the Beaucarnea vs. Nolina controversy, the boundary between Beaucarnea and Calibanus is an issue that has not yet been addressed. Here we show that Beaucarnea is a well‐supported entity, distinct from Nolina on molecular and morphological grounds. Additionally, we demonstrate the absence of reciprocal monophyly between Beaucarnea and Calibanus and formally include Calibanus within Beaucarnea. These decisions were based on maximum parsimony, Bayesian, and maximum likelihood analyses of datasets including ten species of Beaucarnea, two species of Calibanus, six species of Nolina, and five species of Dasylirion, with sequences from the nuclear ITS and plastid trnL‐F and ycf1 regions. Our taxonomic decisions were also based on morphological observations of herbarium specimens and on the literature. We illustrate the diagnostic features of the genera with phylogenetic character mapping. Finally, we offer a redescription of Beaucarnea to accommodate the former Calibanus species and give a key to the taxonomically valid Beaucarnea species.

The Deep Evolutionary Relationships of the Morphologically Heterogeneous Nolinoideae (Asparagaceae) Revealed by Transcriptome Data

“…The nolinoids were previously represented as Nolinaceae including the four genera Beaucarnea Lem., Calibanus Rose, Dasylirion Zucc., and Nolina Michx. from the southern states of the United States through Mexico into Guatemala ( Rojas-Piña et al, 2014 ). They were excluded from Agavaceae and placed close to Dracaenaceae, featured with arborescent, anomalously woody plants; terminal rosette leaves; and indehiscent fruits ( Dahlgren et al, 1985 ).…”

“…from the southern states of the United States through Mexico into Guatemala (Rojas-Piña et al, 2014). They were excluded from Agavaceae and placed close to Dracaenaceae, featured with arborescent, anomalously woody plants; terminal rosette leaves; and indehiscent fruits (Dahlgren et al, 1985).…”

Biogeographical History of the Yucatan Peninsula Endemic Flora (Spermatophyta) from a Phylogenetic Perspective1

“…These adaptive morphological characters may be of evolutionary importance for the taxa. For example, Beaucarnea pliabilis (Baker) Rose (Nolinaceae) has a larger number of foliar papillae that protect stomata in contrast to its sister species B. guatemalensis Rose, which grows in humid tropical forests from central Guatemala to northern Nicaragua (Rojas-Piña et al, 2014) (Fig. 3D).…”

Two new species of Nolina (Nolinoideae: Asparagaceae) endemic to Western Mexico

“…Based on phylogenetic analyses including molecular and morphological data, Nolina was found to be closely related to Beaucarnea Lemaire (1861: 59) and Dasylirion Zuccarini (1838: 258) within the Asparagaceae (Kim et al 2010, Seberg et al 2012, Rojas-Piña et al, 2014. In a previous phylogeographic study of N.…”