Pharbitis caerulea Wall.

Turner, I. M., 2011, The contribution of Sir William Brooke O’Shaughnessy (1809 - 1889) to plant taxonomy, Phytotaxa 15, pp. 57-63 : 59

Pharbitis caerulea Wall.

Ipomoea nil (L.) Roth (1797: 36) . Convolvulus nil Linnaeus (1762: 219) . Pharbitis nil (L.) Choisy (1834: 441) . Type: Dillenius, Hort. Eltham. 1 (1732) 96, t. 80 f. 91 (lectotype, designated by Verdcourt (1957)).

Ipomoea caerulea Roxb. ex Ker Gawler (1818 : t. 276). Convolvulus caeruleus (Roxb. ex Ker Gawl.) Sprengel (1824: 593) , as ‘ coeruleus ’. Pharbitis caerulea (Roxb. ex Ker Gawl.) Wall. in O’Shaughnessy (1841: 505). Lectotype (designated here): Ker Gawler, Bot. Reg. 4 (1818) t. 276. Epitype (designated here): cult. in Hortus Botanicus Calcuttensis, [EIC 1373.3] (K-W)).

Pharbitis caerulea is the only new combination made in The Bengal Dispensatory that appears in IPNI (www.ipni.org). The combination is credited to Wallich in the book and based on ‘ Ipomoea caerulea Kön. ’ with a reference to the second edition of Roxburgh’s Flora Indica ( Roxburgh 1832). The species had actually been included in the first edition (Roxburgh 1824) based on a name supplied by J. König. However many of Roxburgh’s species, because they were mostly published posthumously from manuscripts that had been wholely or partly in circulation, were validated at earlier dates by other authors. Ipomoea caerulea first appeared in The Botanical Register in 1812. The author of the text in the early volumes was John Bellenden Ker Gawler ( Stafleu & Cowan 1979). The species was described and illustrated from material grown from seed at the nursery of Whitley & Co. in Fulham, London. The seed had been obtained from the Botanic Garden in Calcutta presumably under the name Ipomoea caerulea . Ker Gawler cited ‘Roxb. corom. ined.’, which presumably is a reference to manuscript material that Roxburgh sent to Sir Joseph Banks who was overseeing publication of Roxburgh’s Plants of the Coast of Coromandel. I have not been able to trace any herbarium specimens (BM, K) relating to the material of Ipomoea caerulea described or drawn in The Botanical Register and therefore I lectotypify the species to the illustration prepared by Sydenham Edwards. The Wallich Herbarium contains specimens named Ipomoea caerulea that were cultivated in the Calcutta Botanic Garden and I designate one of these as epitype. The plant is correctly referred to Ipomoea nil (L.) Roth.