Does leaf anatomy aid in species identification of Butia (Arecaceae)?

Abstract

Our paper presents reliable anatomical characters of the pinnae that allowed the identification of the recognized species of Butia through a purely anatomical key, in which specific identification is performed by a set of up to five characters. Leaf anatomy, already used to support new taxa in related genera, can also be useful to validate questionable Butia species and differentiate between similar species, but surprisingly does not reflect the proposed phylogenetic relationship between species of this genus.

Diversity of leaf anatomy within a single leaflet and between leaflets of four Butia (Arecaceae, Arecoideae) species

“…Noblick's paper (2013) showed how leaflet anatomy could be used to support molecular data (Meerow et al 2009). Our study suggests that we need to take a step back and re-examine our previous data to reconfirm and re-evaluate the characters we have been using in our identification keys (Noblick 2013(Noblick , 2017Sant'Anna-Santos et al 2018;Firmo et al 2021) or in establishing our systematic relationships. As we have seen from this study, leaflet anatomy does vary even between leaflets that are literally adjacent to or directly opposite each other as in Butia paraguayensis (Table 4, Figure 10).…”

“…1) Vascular bundles with enlarged sheaths (vbe) -These are a thick sclerenchymous fibre strands with a small portion of vascular tissue. They have been referred to as marginal veins somewhat enlarged (Tomlinson et al 2011), vascular bundles with exaggerated sheaths (Noblick 2013(Noblick , 2017 or vascular bundles with reinforced sclerenchymous sheaths (Sant'Anna-Santos et al 2018). These are found on the edge of the leaflet margin.…”

“…Tomlinson (1961) hinted that leaf anatomy might be useful in palm identification. It was used to identify species of Syagrus (Glassman 1972;Noblick 2013Noblick , 2017Firmo et al 2021) and, more recently, species of Butia (Sant'Anna-Santos et al 2015, 2018. Sanin and Galeano (2011) used leaf anatomy to distinguish species of Ceroxylon Bonpl.…”

“…While Glassman (1972) and Noblick (2013Noblick ( , 2017 found plenty of characters in the leaflet margin to distinguish species of Syagrus, finding differences in the leaflet margins to distinguish Butia species has been challenging, even while Butia's isolateral, nearly mirrored anatomy is one of its most compelling and distinguishing generic characters. Although differences in Butia leaflet marginal anatomy have failed to distinguish most species, Sant'Anna-Santos et al (2015, 2018 discovered that there were important differences found in the mid-ribs, an issue previously stated by Glassman (1972). They used these characters to confirm the dissimilarities between Butia capitata (Mart.)…”

“…and Butia odorata (B.Rodr.) Noblick (Sant'Anna-Santos et al 2015) and also to construct a key to the various other Butia species (Glassman 1972;Sant'Anna-Santos et al 2018). Recently, the leaflet anatomy was employed in the description of a new species of Butia, Butia buenopolensis .…”