Habit and stems
Leptocereus bayahibensis is 2–5 m tall. Large woodland plants have a trunk 1.5–2.5 m long and 200–250 mm in diameter. Terminal segments may be about 1 m long and 25–40 mm in diameter, with (5–)6(–7) ribs. The margins are undulate. Areoles are spaced about 15 mm apart and their felt is initially reddish-brown, becoming white. They usually bear 15–20 straight spines measuring 12–25 mm. [Hoxey et al. 2023b, pp. 57–61]
The coast and Saona Island
The 2023 revision restricts the known range to La Altagracia Province. Sites were described around Bayahíbe, Boca de Yuma, Punta Cuevita and Punta Cana, and on the northern coast of Isla Saona. All sites known to the authors lay within about 2 km of the sea, up to 50 m above sea level. Plants grew on coral limestone with little soil. On exposed cliffs and in low coastal vegetation they were usually smaller than in the Bayahíbe woodland. [Hoxey et al. 2023b, pp. 58–61]
Flowers and fruits with short spines
The flowers open after dusk and remain open beyond dawn. They are 50–60 mm long and about 15 mm wide. The tube is almost spineless or bears 2–3 weak spines up to 1 mm long per areole. Fruits measure 70–100 × 50–60 mm and contain seeds in mucilaginous pulp. Fruit spines are often absent. When present, they are slender and 2–5 mm long. Seeds measure 2.4–2.7 × 1.4–1.6 × 0.8 mm. [Hoxey et al. 2023b, pp. 58–61]
Historical identifications
Plants from this region were long described as L. weingartianus. The revision distinguished them using habit, flowers, short shoots, fruits and seeds. Large woodland specimens may resemble L. paniculatus, but have much thinner terminal segments. Such similarities provide a basis for morphological comparison. The paper did not present a phylogeny confirming the new species’ closest relationship. [Hoxey et al. 2023b, pp. 61]