Nicotiana gibbosa M.W.Chase, D.D.Andrew & J.J.Bruhl, 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 : 176-179

Nicotiana gibbosa M.W.Chase, D.D.Andrew & J.J.Bruhl , sp. nov.

( Fig. 10–12 .)

Type: New South Wales. Oxley Wild Rivers National Park, ~ 170 m from the end of Long Point Picnic Area Rd along Chandler View Circuit , 1018 m, 30°39′53.7″S, 151°56′4.4″E, 18 Feb. 2021, Andrew 240 & Bruhl (holo: NSW; iso: K, NE 111501 ) .

Diagnosis

Nicotiana gibbosa is sister ( Fig. 1 a ) and morphologically similar to N. forsteri ( Fig. 13), but it has a flower three times the size, a different inflorescence structure with a single main axis and limited basal branching ( v. extensive basal branches), narrower petiole wings and reduced auriculate bases. Both have protrusions on the exterior of the floral tube where the filaments are attached to the tube and pustules on the leaves with a single terminal hair, although these are much more obvious and frequent in the latter.

Erect, herbaceous, annual herbs, forming a minimal rosette, but with numerous large leaves in the basal portion of the stems, the main stem with major branches in the upper half of the inflorescence, but only a few small ones in the lower half. Leaves with narrowly winged petioles, the wing 1.6–4.0 cm wide, bullate, blades 20.0–36.5 × 3.2–13.4 cm (including petiole), broadly ovate, the apex blunt to acute in the basal leaves, becoming acuminate in those higher up; upper leaves, base gently attenuate, weakly auriculate, margins entire, undulate, often basally bullate, uppermost leaves sessile often with a somewhat auriculate base. Vestiture composed of dense, short-haired glands on all surfaces, leaf laminas with a few raised pustules with a terminal, twisted longer hair. Inflorescence bracts sessile, linear lanceolate, ~ 0.5–2.3 cm long, the apex acuminate. Calyx 1.2–1.4 × 0.3–0.4 cm, one lobe slightly longer and one shorter than the others, the tips acuminate, slightly flaring, 0.3–0.5 cm longer than and surrounding the fruit, the calyx persistent and enlarged at maturity. Flowers white, pendent to slightly out-facing, lower part of the floral tube longer than the upper and projecting outward, the upper part reflexed backward. Corolla tube 3.2–3.6 cm long (from tip of the calyx), 0.3 cm in diameter at the apex of calyx and 0.5 cm in diameter in the middle, with a weak throat cup and prominent bulges where the filaments connect to the floral tube, the limb 3.1–3.5 cm across, the lobes slightly cleft, cleft 0.1 cm deep, sinus 0.4 cm deep, lobes 1.4–1.6 cm long; four stamens near throat of the floral tube, lower pair 0.2 cm longer than the upper pair, and the fifth ~ 0.5 cm deeper in the tube, all with the filaments 0.4–0.6 cm long and attached to the floral tube in pockets. Fruit a capsule splitting in four lobes, 0.8–1.2 cm long at maturity.

Distribution

Known thus far only from a few collections on the Northern Tablelands of New South Wales at Long Point, Curricabark Creek and Wollomombi Falls and the Macleay River on the New South Wales North coast ( Fig. 14 ).

Habitat and ecology

Growing in the transition between eucalypt grassy to layered open forest and low closed forest (dry rainforest) as attested by the range of closed forest elements at the known sites ( Fig. 14 ). From the available fire records, it seems that three of the known four sites were some distance from recent fires. The type locality had suffered severe drought followed by above-average summer rainfall in February 2021. Rainfall records for the Williams collection indicated that it was also collected in a season with above-average rainfall.

Phenology

Collected in flower in February–March and October. We suspect that it could flower at any time of the year, depending on disturbance (including fires) and rainfall.

Etymology

Named for the pouches in the middle of the floral tube inside which the filaments are attached, from the Latin gibbosus (pouched).

Chromosome number

Unknown.

Notes

Observations and collections of Nicotiana that are or are likely to be N. gibbosa have been referred to N. forsteri ( Fig. 13), which is frequent in rainforest, dry rainforests and vine scrub vegetation all along the eastern coast of Australia and on Lord Howe Island and New Caledonia ( Marks 2010). Thus far, N. gibbosa appears to have been collected only a few times and only in seasons of above-average rainfall following disturbance events (drought or fire). The type locality will be monitored for its occurrence. Nictotiana gibbosa is recorded generally at higher elevations than is N. forsteri .

Specimens examined

NEW SOUTH WALES. 1.7 km due N of ‘Kunderang East’ Station, Mackay [Macleay] River, plants in dense regeneration from moderately intense wildfire near the edge of dry rainforest, 220 m, 15 Oct. 1991, 30.8033°S, 152.144°E, Pollock s.n. ( NSW 269628); Curricabark Wildlife Refuge, Curricabark Creek in the Pigna Barney River catchment, 785 m, 1996, 31°47′30″S, 151°37′20″E, Robinson s.n. ( NSW 447376); Wollomombi Falls, in wet scrub with Alectryon forsythii , Notolaea microcarpa, Mar. 1962 , 30°32′S, 152°3′E, Williams s.n. ( NE 22881).

Figures

Fig. 10. Nicotiana gibbosa based on living plants cultivated at the Royal Botanic Gardens, Kew, grown from seeds associated with the holotype Andrew 240 & Bruhl, Long Point area past Hillgrove, Oxley Wild Rivers NP, New South Wales, vouchered as Chase & Christenhusz 21007 (K). Painted by Deborah Lambkin.

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).

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.