Solanum pseudogracile Heiser, Bot. J. Linn. Soc. 76: 294. 1978

Knapp, Sandra, Barboza, Gloria E., Bohs, Lynn & Saerkinen, Tiina, 2019, A revision of the Morelloid Clade of Solanum L. (Solanaceae) in North and Central America and the Caribbean, PhytoKeys 123, pp. 1-144 : 83-85

13. Solanum pseudogracile Heiser, Bot. J. Linn. Soc. 76: 294. 1978 Figures 39 , 40

Type.

United States of America. North Carolina: Onslow County, N of Surf City, North Carolina Hwy. 210, 16 Jul 1960, C.R. Bell 17061 (holotype: IND [IND-0136007, acc. # 145606]; isotype: IND [IND-0136008, acc. # 145605], NCU [NCU00062742]).

Description.

Subwoody annual herb to perennial shrub up to 1.0 m tall, branching at base. Stems terete or with minute spinescent processes, green-grey to straw colour, sparsely to moderately pubescent with simple, appressed, uniseriate eglandular 4-9-celled trichomes, these ca. 0.8 mm long; new growth more densely pubescent. Sympodial units difoliate, not geminate. Leaves simple, (1.3)1.8 –8.3(– 10.5) cm long, (0.6 –)1.1– 3.7 cm wide, ovate-lanceolate to narrowly ovate, slightly discolorous, green above and pale grey underneath; adaxial surface sparsely pubescent with appressed translucent, simple, uniseriate trichomes like those on stem, these denser along the veins; abaxial surface more densely pubescent like those of the upper surface evenly across lamina and veins; primary veins 3-5(6) pairs; base attenuate to acute, slightly unequal; margins entire to occasionally shallowly sinuate dentate; apex acuminate to acute; petiole (0.7 –)1.0– 2.4 cm long, pubescent with simple uniseriate trichomes like those of the stems and leaves. Inflorescences 1.2-2.0 cm long, lateral, internodal, unbranched or rarely forked, then with rhachis 0.4-0.5 mm long, with 3-8 flowers spaced along the rhachis, sparsely pubescent with appressed simple uniseriate trichomes like those on stem; peduncle 1.2-1.8 cm long, straight; pedicels 5-8 mm long, 0.2-0.3 mm in diameter at the base and 0.5-0.6 mm in diameter at the apex, straight and spreading, articulated at the base; pedicel scars spaced ca. 0-1 mm apart. Buds ellipsoid, corolla exserted from the calyx to 2/3 of its length. Flowers 5-merous, all perfect. Calyx tube 1.0-1.5 mm long, the lobes 0.5-1.0 mm long, ca. 1 mm wide, broadly ovate to obovate with obtuse to shortly acute apices, sparsely pubescent with appressed hairs like those on stem but shorter. Corolla 10-12 mm in diameter, deeply stellate, white with a yellow-green central portion near the base, some with darker blackish-purple colouration around the central star, lobed 2/3 to 4/5 to the base, the lobes 4.0-5.0 mm long, 1.6-3.0 mm wide, strongly reflexed at anthesis, later spreading, densely pubescent abaxially with simple uniseriate trichomes like those on stem and leaves but shorter. Stamens equal; filament tube minute; free portion of the filaments 0.6-1.0 mm long, adaxially pubescent with tangled uniseriate 4-6-celled simple trichomes; anthers 2.2-2.6 mm long, 0.5-0.7 mm wide, ellipsoid, yellow, poricidal at the tips, the pores lengthening to slits with age. Ovary globose, glabrous; style 3.5-4.0 mm long, exserted up to (1.0-)2.5 mm beyond the anther cone, densely pubescent with 2-3-celled simple uniseriate trichomes at the base; stigma capitate, minutely papillate, green in live plants. Fruit a globose berry, (4-)8-14 mm in diameter, dull purplish-black at maturity, opaque, the surface of the pericarp matte and somewhat glaucous; fruiting pedicels 7-10 mm long, 0.3-0.4 mm in diameter at the base, (0.6-)0.9-1.0 mm in diameter at the apex, deflexed, becoming woody, pedicels spaced (0)0.5-3.0 mm apart, dropping with mature fruits; fruiting calyx not accrescent, the tube 1.0-1.5 mm long, the lobes 2.5-3.0 mm long, lobes reflexed in fruit. Seeds 20-50(-60) per berry, 1.1-1.3 mm long, 0.8-0.9 mm wide, flattened and tear-drop shaped with a subapical hilum, pale yellow, the surfaces minutely pitted, the testal cells pentagonal in outline. Stone cells absent (very rarely 2). Chromosome number: 2n =2 × =24 ( Heiser et al. 1965; Heiser et al. 1979).

Distribution.

(Figure 41 ) Solanum pseudogracile is endemic to the southeastern United States of America from the Atlantic coast of the Carolinas to the Gulf Coast in Florida and Alabama. Although we have seen no collections yet, we expect this species to also occur in the Bahamas.

Ecology.

Occurring on sand dunes, sandy moist banks and disturbed areas between 0-400 m elevation. Solanum pseudogracile is ecologically distinct from S. americanum in growing mostly on hummocks in salt marches or on sand dunes, as an epiphyte on palm trees, on walls, and among dense hedgerows.

Common names.

United States of America. Glowing nightshade ( USDA Plants 2017). The common name of Coastal-dune nightshade ( NatureServe 2017) attributed to S. gracilius Herter likely refers to S. pseudogracile .

Uses.

None recorded.

Preliminary conservation status ( IUCN 2017).

Least Concern (LC). Solanum pseudogracile is common and weedy in coastal habitats in the southeastern United States. For EOO see Table 6 . [NB: the Midwest Plants consortium is not showing locality data in North Carolina because of conservation threat - see http://midwestherbaria.org/portal/collections/individual/index.php?occid=15549149&clid=0]

Discussion.

Solanum pseudogracile is a species of the eastern North American coastal plain, and usually occurs in coastal areas not far from the sea. It is very similar to the adventive S. chenopodioides and can be very difficult to distinguish from it. Solanum pseudogracile has longer rectangular to obovate calyx lobes that are rounded to acute at the apex and reflexed in fruit, while S. chenopodioides has short triangular calyx lobes that are acute at the apex and always appressed in fruit. In addition, S. pseudogracile has a longer style that extends (1)2.0-2.5 mm beyond the anther cone, compared to S. chenopodioides where the style is exserted only to 1.5 mm beyond the anther cone. The species differs from S. nigrescens in lacking stone cells or rarely having 2, while S. nigrescens always has 4-13 stone cells per fruit. In the absence of fruit these two species can be very difficult to distinguish; they are widely sympatric along the Gulf Coast of the southern United States of America.

Solanum pseudogracile may be merely a form of S. chenopodioides , with which it shares many characteristics such as appressed white pubescence and absence of stone cells, but further population level work using molecular and other field markers will need to be undertaken. Distinguishing features of these morelloid species often disappear in herbarium specimens (see D’Arcy 1974b), making analysis using herbarium specimens difficult. Nee (pers. comm.) has seen plants he has identified as the two taxa growing together. The Florida plants identified as S. americanum var. baylisii by D’Arcy (1974b) fit our concept here of S. pseudogracile , while the type of D’Arcy’s variety is a plant of S. chenopodioides collected from New Zealand. Many of the plants identified as S. chenopodioides in the Florida Plant Atlas (http://florida.plantatlas.usf.edu/) are most likely S. pseudogracile .

In describing S. pseudogracile Heiser (1978) cited only IND. There are two sheets of Bell 17061 in IND, one annotated type. We select this sheet (IND-0136007) as the lectotype for S. pseudogracile ; the sheets are not numbered sheet 1 and sheet 2 as was done by Heiser for other species in this group (e.g., S. costaricense , S. leonii ).

Specimens examined.

See Suppl. materials 1 and 3.

Figures

Figure 39. Solanum pseudogracile Heiser. A Habit B fruiting habit C bud D flower E dissected flower F mature fruits G dried berry H seed (A-H Kearney 1250). Drawing by C. Banks.

Figure 40. Solanum pseudogracile Heiser. A Flowering branches B flowers at full anthesis C developing fruits D mature fruits (A, B, D Nee & McClelland 60216 C Nee & McClelland 60224). Photos by M. Nee.

Figure 41. Distribution of Solanum pseudogracile Heiser.