Ipomoea revoluta J.R.I.Wood & Scotland, 2017

Wood, John R. I., Munoz-Rodriguez, Pablo, Degen, Rosa & Scotland, Robert W., 2017, New species of Ipomoea (Convolvulaceae) from South America, PhytoKeys 88, pp. 1-38 : 22-23

Ipomoea revoluta J.R.I.Wood & Scotland sp. nov. Figure 14

Diagnosis.

Ipomoea revoluta is almost certainly related to I. malvaeoides Meisn. and its allies but is distinguished from all of these by its twining (not erect) habit and distinctly petiolate leaves. Related species in which the leaves are furnished with linear leaflets, such as I. fiebrigii O’Donell, I. itapuaensis J.R.I. Wood & R. Degen and I. theodori O’Donell, are erect herbs with sessile or near sessile leaves.

Type.

BRAZIL. Mato Grosso do Sul, Serra de Maracaju , 17 Feb. 1970, G. Hatschbach 23761 (holotype MBM, isotypes CTES, F, MICH, S) .

Description.

Slender twining liana of unknown height; stem woody, c. 2-3 mm thick, pale brown, shortly pubescent. Leaves petiolate, digitately divided into 5-7 free leaflets; leaflets 5-9 × 0.15-0.4 cm, linear, attenuate to a mucronate apex, basally tapered, margin revolute; adaxially glabrous, midvein strongly impressed; abaxially white-tomentose, the midvein prominent, nearly glabrous; petioles 8-13 mm, thinly pubescent. Inflorescence of 1-3-flowered axillary cymes; peduncles 7-9 mm, very thinly pubescent with scattered hairs; bracteoles c. 1 mm long, scale-like, caducous; pedicels 8-10 mm long, very thinly pubescent with scattered hairs; sepals subequal, 8-10 × 6-7 mm, ovate to elliptic, acute to shortly mucronate, sericeous with narrow, scarious, glabrous margins, inner sepals white-sericeous with wider scarious margins; corolla 5-6 cm long, pink, sericeous in bud, funnel shaped from a short basal cylindrical tube, limb c. 2 cm diameter, lobes rounded; stamens unequal, filaments pilose at base only, the two longer c. 20 mm, the shorter c. 12 mm; anthers included; ovary bilocular, glabrous; style c. 20 mm, stigma bi-globose. Capsule ovoid, apiculate, c. 10 mm long (immature), glabrous, ± enclosed by the sepals.

Distribution.

BRAZIL. Apparently endemic to the Serra de Maracaju in Mato Grosso do Sul, where it grows on arenite outcrops. Figure 9

Additional collection seen.

Mato Grosso do Sul, G.M. Hatschbach & J.M. Silva 60724 (MBM).

Conservation status.

The two collections were made at different dates from the near vicinity of each other. Field notes do not indicate the plant’s frequency and in the absence of other collections or any information about threats to its habitat, it can only be classified as Data Deficient (DD) within IUCN guidelines. It would be treated as a "black star" species within the classification of Hawthorne and Marshall (2016), but again this must be considered a provisional classification as no systematic search has been made for the species at the type locality or in other suitable habitats, although it must be presumed to be rare.

Etymology.

The epithet revoluta refers to the revolute margins of the leaflets.

Note.

We have not been able to sequence material of this species but it is almost certainly related to I. malvaeoides and its allies, which are part of a large clade of around 70 species almost restricted to South America. Species in the clade are characterised morphologically by the pubescent exterior of the corolla and the subequal, sericeous or pubescent, ovate herbaceous sepals. The linear leaflets of I. revoluta recall those of the unrelated I. subrevoluta Choisy, with which it has been wrongly identified in many herbaria. It is easily distinguished from that species by the sericeous exterior of the corolla and the larger, abaxially pubescent sepals.

Figures

Figure 9. Map of Eastern Brazil showing distribution of I. ensiformis, I. fasciculata, I. kraholandica, I. longirostra, I. revoluta, I. scopulina, I. veadeirosii, and I. walteri.

Figure 14. Ipomoea revoluta. A habit B adaxial leaf surface C abaxial leaf surface D inflorescence E outer sepal F middle sepal G inner sepal H corolla opened out to show stamens J calyx enclosing capsule. Drawn by Rosemary Wise from G. Hatschbach 23761.