Ipomoea cuscoensis J.R.I.Wood & P. Munoz, 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 : 5-9

Ipomoea cuscoensis J.R.I.Wood & P. Munoz sp. nov. Figures 3 , 4

Diagnosis.

Ipomoea cuscoensis is a distinct species because of its glabrous indumentum, 3-5-lobed leaves, large ovate-elliptic scarious-margined sepals and striking purple corolla. It is most likely to be confused with I. peruviana O’Donell and I. clavata (G. Don) Ooststr. ex J.F. Macbr., but differs from both in the purple corolla, c. 6.5 cm long, and in having all leaves 3-5-lobed. I. peruviana differs additionally in its much larger (10-11 cm long), very pale blue corolla and mostly entire leaves while I. clavata differs in its solitary blue flowers and pilose stems.

Type.

PERU. Cusco: Anta, Sisal, Limatambo , 2300 m, 15 March 1963, C. Vargas 14325 (holotype CUZ, isotype US).

Description.

Twining perennial of unknown height; stems glabrous. Leaves petiolate, 3-6 × 3-6.5 cm, 3-5-lobed, the terminal lobe larger, lobes elliptic in outline, apex acuminate to an obtuse mucronate tip, base shallowly cordate, margin weakly crenate, both surfaces glabrous, abaxially paler with prominent whitish veins; petioles 1.3-3 cm. Inflorescence of pedunculate axillary cymes with up to 7 flowers; peduncles 4 -6 cm, glabrous; bracteoles caducous, not seen; pedicels 8-20 mm, glabrous; calyx narrowly ovoid, sepals somewhat unequal, outer sepals 20-22 × 10 mm, ovate to ovate-elliptic, shortly mucronate, glabrous, margins scarious; inner sepals 15 × 8 mm, ellipsoid, mucronate, the scarious margins broad; corolla 6.5 cm long, campanulate, glabrous, deep pink, limb 3-4 cm diameter. Capsule and seeds unknown.

Distribution and habitat.

Endemic to dry forest and scrub at 2100-2700 m in Southern PERU. Figure 5 .

Additional collections seen.

Apurimac: Abancay, Cachora, 2700 m, 17 Jan 1950, C. Vargas 9083 (CUZ); Grau, bajando a Kai Ranka, 2400 m, 9 March 1946, C. Vargas 5826 (CUZ). Cusco: Anta, Río Blanco, 2100 m, 22 March 1971, C. Vargas 22075 (CUZ); Mollepata, 2710 m, 3 May 2003, W. Galiano et al. 5146 (MO).

Conservation status.

Although we have seen five separate collections of this species, they all come from a restricted area of Peru and the labels provide no information about the plant’s frequency. It should probably be treated as a "black star" species within the classification of Hawthorne and Marshall (2016) and be classified as Endangered (EN) within IUCN (2012) guidelines because of an area of occupancy of <12, 000 km², based on an analysis using GEOCAT. However, these classifications should be treated as provisional until a full field evaluation is carried out.

Etymology.

The epithet " cuscoensis " refers to the Cusco region to which this species is endemic.

Notes.

Phylogenetic analysis using ITS sequences (unpublished data) indicates that this species belongs to a small clade, which includes I. lindenii M Martens & Galeotti, I. corymbosa (L.) Roth ex Roem. & Schult. and I. clavata , all of which are characterised by their relatively large sepals. It has been confused with I. peruviana both in the herbarium and also by Wood and Scotland (2017b), partly because I. peruviana is poorly known and partly because images of I. cuscoensis have only recently become available to us after Muñoz’s visit to CUZ in April 2017. These make clear the very distinctive flowers of the new species and confirm that it grows at the relatively high altitude of 2100 to 2710 m, at a much higher elevation than the lowland I. peruviana .

Figures

Figure 3. Ipomoea cuscoensis. A habit B habit; C outer sepal; D inner sepal. Drawn by Rosemary Wise from Galiano et al. 5146.

Figure 4. Image of Vargas 22075 showing the distinctive purple flowers of Ipomoea cuscoensis.

Figure 5. Map of equatorial South America showing the distribution of Ipomoea cuscoensis (●), I. graminifolia (✖), I. uninervis (▲) and I. velutinifolia (■).