Nicotiana bungonia M.W.Chase & Taseski, 2023

Bruhl, Jeremy J., Andrew, Damien D., Palsson, Ruth, Jobson, Richard W., Taseski, Guy M. & Samuel, Rosabelle, 2023, Nine new species of Australian Nicotiana (Solanaceae), Australian Systematic Botany 36 (3), pp. 167-205 : 195-197

Nicotiana bungonia M.W.Chase & Taseski , sp. nov.

( Fig. 26.)

Type: New South Wales. Bungonia Gorge, Bungonia National Park, along Mount Ayre Track , ~ 250 m east of Mount Ayre, 478 m, 34°48′9.71″S, 150°1′44.64″E, 30 Dec. 2020, Taseski 1398 (holo: NSW; iso K) .

Diagnosis

Nicotiana bungonia is morphologically similar to N. suaveolens , to which specimens were previously assigned, despite their atypically small flowers (0.5–0.6 v. 2.2–4.2 cm long respectively). It also differs in its highly branched inflorescences. It could also be mistaken for N. goodspeedii , to which it is similar in flower size and shape and branched inflorescence, but it differs in its wider leaves and sparser pubescenc; N. goodspeedii has only a few hairs on the bases of its stems and leaves to none.

Erect herbaceous, annual to short-lived perennial herbs, up to 1.0 m tall, almost no rosette, numerous large leaves in the basal portion of the stems and few in the upper portions, the major branches from near the base with many side branches. Leaves with narrowly winged petioles, up to 0.8 cm wide and 4.5 cm long, blades 3.7–15.8 × 1.5–10.5 cm (including petiole), ovate-lanceolate, the apex acute in the basal leaves to acuminate in those higher up, base gradually to abruptly attenuate, uppermost leaves sessile, bract-like, margins entire, undulate, ciliate, often minutely dentate and basally bullate. Vestiture composed of long, somewhat curly, non-glandular hairs on the leaf margins and main veins and basal stems, but becoming nearly glabrous on the upper stems, ultimate stems, calyces and peduncles, with short glandular hairs and a few longer, curly, non-glandular, multicellular hairs with a swollen base. Calyx 1.0–1.2 × 0.1–0.2 cm, one lobe slightly longer and one shorter than the others, the tips acuminate, clasping to reflexed, slightly longer than and surrounding the mature fruit, the calyx enlarged at maturity. Corolla tube white to pale green, 0.5–0.6 cm long (from tip of the calyx), 0.2–0.3 cm in diameter, without a throat cup, the limb white, 0.5–0.8 cm across, the lobes minutely cleft, cleft 0.1 cm deep, sinus 0.1–0.2 cm deep, lobe 0.3–0.4 cm long; four stamens of the same length 0.1 cm inside throat of the floral tube and the fifth ~ 0.2–0.3 cm deeper in the tube, all with the filaments 0.2–0.3 cm long. Fruit a capsule, 0.6–0.8 cm long, splitting in four lobes.

Distribution

Known thus far only from Bungonia Gorge, south-eastern New South Wales ( Fig. 14 ).

Habitat and ecology

In open Eucalyptus agglomerata woodland on steep valley walls and ridgetops, growing in a variety of substrates, including siltstone, mudstone, shale transition areas and limestone.

Phenology

Collected in flower in November and December.

Etymology

Named for the Bungonia Caves, a name of Aboriginal origin, meaning ‘sandy creek’ in the Ngunnawal language (Geographical Names Board of New South Wales, https:// www.gnb.nsw.gov.au). The epithet is a noun in apposition.

Chromosome number

Unknown.

Notes

The habit of Nicotiana bungonia is similar to that of N. suaveolens , but the flowers are much smaller than those of the latter. Both occur on or are associated with limestone, often around caves. One of the other two specimens cited below was annotated by Horton in 1979 as N. suaveolens , but she noted on the label that the corolla was ‘unusually short’. The species falls within the larger N. suaveolens clade, but not close to the latter ( Fig. 1 b ). We thought at first that it might be a hybrid between N. suaveolens and perhaps N. goodspeedii , but it has been collected in Bungonia Gorge for over 50 years and sets abundant seeds, which would be unlikely if it were a hybrid between these two species (n = 16 and n = 20; Chase et al. 2022 b). Chromosomes have yet to be studied, but its genome size is similar to others in the N. suaveolens clade (1 C = 3.6 pg; S. Mian, RBG, Kew, unpubl. data), so it is not a neoallopolyploid such as N. notha M.W.Chase & Christenh. (Chase et al. 2021 c) . Genetically, it is distinct ( Fig. 1 b ) and does not exhibit an admixture of these two species ( L. A. Cauz-Santos and M. W. Chase, unpubl. data). Secondary vouchers grown from seeds associated with the type collection, Chase & Christenhusz 2011 ( NSW, CANB) were included in the phylogenetic analysis ( Fig. 1 b ).

Specimens examined

NEW SOUTH WALES. South edge of Bungonia Gorge, ~ 0.25 miles [400 m] north-west of main Bungonia Lookdown , extensively outcropping limestone forming a series of low cliffs with intervening ledges, Dec. 1965, 34.8°S, 150.02°E, Rodd s.n. ( NSW 101138 !); Bungonia Gorge , south of Marulan , Southern Highlands , 34.8°S, 150.02°E, 10 Nov. 1966, Pullen 4173 A ( CANB 162437 !; NSW 99788 !) .

Figures

Fig. 14. Map of the distributions of Nicotiana megalosiphon (green circles), N. latifolia (red circles), N. sessilifolia (blue circles), N. gibbosa (rose-purple circles), N. praecipitis (orange circle) and N. bungonia (aqua circle). Created by Maarten Christenhusz from data downloaded from the Australasian Virtual Herbarium website.

Fig. 1. Phylogenetic tree for the species of Nicotiana section Suaveolentes, based on the RADseq (nuclear) data matrix of Chase et al. (2021, 2022b), to which we have added the accessions for the new species reported in this paper. Vouchers for these added accessions are indicated under the additional specimens examined for each of the new species. All nodes for which there are no bootstrap percentages indicated are 100. (a) The basal nodes of the RADseq tree. (b) The more derived clades in the same RADseq tree as in (a).