UNEXPECTED DIVERSITY OF AUSTRALIAN TOBACCO SPECIES (NICOTIANA SECTION SUAVEOLENTES, SOLANACEAE)

Abstract

This special issue highlights some of the wonderful species of native Australian tobacco (Nicotiana sect. Suaveolentes). We here present twelve species of this genus, four of which are new to science. Many Nicotiana species have a high ornamental value, and we hope that particularly the rarer Australian species will find a way into horticulture to prevent them from becoming threatened. This would allow maintenance of ex-situ populations, mitigating the effects of changing climate and introduction of invasive species. Tobaccos dispersed into the Australian outback around two million years ago and are now radiating there. It has been clear that they have interesting cytological evolution as well as morphological differences. They appear to have peculiar drought adaptations, which are needed for thin-leaved herbs growing in some of the driest places on the planet.

Repetitive DNA Restructuring Across Multiple Nicotiana Allopolyploidisation Events Shows a Lack of Strong Cytoplasmic Bias in Influencing Repeat Turnover

“…Section Suaveolentes is the oldest (ca. 6 Ma; [18]) and most species-rich [33] group of tetraploids in Nicotiana. In this section, most species have genome sizes that represent stark genome downsizing [34], and N. benthamiana has a genome size of 1C = 3.3 Gbp.…”

, a new Australian species in

“…Unlike other Nicotiana sections, Suaveolentes contains no American taxa and is native to Australia (26 recognised species), the Pacific (three species) and Africa (one species). Australian Suaveolentes taxa are widespread across the continent, especially in the arid zone (Knapp et al 2004;Chase et al 2018a).…”

“…The number of species in section Suaveolentes is currently subject to revision (Chase et al 2018a). Misidentification of available N. section Suaveolentes seed and herbarium material is common, with estimates ranging from 23% to at least 50% (Marks et al 2011a;Chase et al 2018a). For instance, several Western Australian accessions previously described as N. umbratica N.T.Burb.…”

“…As well as misidentified material, there are also undescribed species in N. section Suaveolentes (Chase et al 2018a). One example is an accession related to N. goodspeedii H.-M.Wheeler that was collected by the noted Australian botanist D. E. Symon in 2004 and is currently named Nicotiana sp.…”

SPECIES DELIMITATION IN NICOTIANA SECT. SUAVEOLENTES (SOLANACEAE): RECIPROCAL ILLUMINATION LEADS TO RECOGNITION OF MANY NEW SPECIES

“…In 2018, Chase & Christenhusz (2018a, 2018b) and Chase et al . (2018b) described another four species and one name was resurrected from synonymy (Chase & Christenhusz, 2018c) as part of an earlier themed issue of Curtis's Botanical Magazine (Chase et al ., 2018a, and references therein). Another new species, N. paulineana Newbigin & P.M.Waterh.…”