Asketanthera dolichopetala (Urb.) Woodson

Morales, J. Francisco, 2018, Studies in Neotropical Apocynaceae LIV: a synopsis of Asketanthera, Candollea 73 (1), pp. 7-17 : 12

2. Asketanthera dolichopetala (Urb.) Woodson in Ann. Missouri Bot. Gard. 19: 47. 1932 ( Fig. 2 , 3 ).

Ξ Echites dolichopetalus Urb., Symb. Antill. 7: 335. 1912.

Lectotypus (designated here): DOMINICAN REPUBLIC. Prov. Barahona: near Barahona, road to El Marisal, VII.1910, fl., Fuertes 453 ( S [ S04-1835 ]!; isolecto -: BM!, K [K000582733]!, L [ L0004431 ]!, MO [MO100108]!).

Branchlets moderately to densely puberulent; interpetiolar colleters up to 1.1 mm long. Petioles 12-20 mm long; leaf blades 5.8-10.3 × 3.8-6.2 cm, ovate-elliptic to elliptic, the apex acuminate, the base broadly acute to abruptly attenuate, very sparsely strigulose to hirsutulous on both surfaces, secondary veins slightly impressed abaxially, not visible adaxially. Inflorescence densely to moderately puberulent, 8-13-flowered, peduncle (30-) 35-55 mm long, pedicels 5-9 mm long, bracts 7-15 × 1.5-5 mm, elliptic to linear-elliptic; sepals 12-18 × 4-6.5 mm, elliptic to ovate-elliptic, the apex narrowly acuminate, moderately to sparsely hirsutulos externally, the colleter irregularly erose at the apex. Corolla cream, densely hirsutulous externally, tube 15-21 × 1.7-3.7 mm, inflated around the stamens, 1.7-2 mm diam. at the orifice; lobes 24-28 × 5.5-7 mm, obliquely obovate-elliptic; stamens inserted in the proximal half of the corolla tube, anthers 6.4-7 mm long, the auricles rounded, style-head 1.5-1.9 mm long; ovary 1.5-2 mm long, glabrous; nectaries c. two-third the length of the ovary, each nectary entire. Follicles unknown.

Distribution, habitat and phenology. – Endemic to the Dominican Republic, where it grows in wet forest, from 90- 600 m. Flowers have been reported in July and December.

Conservation status. – Only two populations from severely fragmented habitats are known for A. dolichopetala . Additional fieldwork might reveal that this species has a wider distribution, but based on the current collections and the reduced AOO (8 km 2), A. dolichopetala is provisionally assessed as “Critically Endangered” [CRB1ab(iii,iv) + B2ab(iii,iv)] following IUCN Red List Categories and Criteria ( IUCN, 2012).

Notes. – Asketanthera dolichopetala is separated from A. calycosa and A. p icardae by its petioles 12-20 mm and inflorescences with long peduncles. Fruiting specimens show some resemblance to A. picardae , but the latter species has shorter peduncles (4-15 mm vs. (30-) 35-55 mm). The holotype of Echites dolichopetalus was destroyed in May 1943 during World War II. The duplicate at S is designated here as the lectotype because is the most complete preserved specimen.

Specimens examined. – DOMINICAN REPUBLIC. Prov. Barahona: Sierra del Bahoruco, La Ciénaga, section La Filipina, cañada La Baliza , 7.XII.2006, fl., Clase 4333 ( CR, MO).

Figures

Fig. 2. – Asketanthera dolichopetala (Urb.) Woodson. A. Habit; B. Adaxial view of one sepal, showing the colleter at the base; C. Corolla bud; D. Anther, dorsal view; E. Style-head, nectaries, and ovary.

Fig. 3. – Distribution map of the four accepted species in Asketanthera Woodson.