Piper khasianum C. DC., Prodr.

Mukherjee, Prasanta Kumar, 2018, Nomenclatural notes on Piper Linn. (Piperaceae) from India II, Phytotaxa 338 (1), pp. 17-32 : 22

10. Piper khasianum C. DC., Prodr. 16(1): 349. 1869.

Type:— INDIA: Meghalaya: mont. Khasia, 4000ft. J. D. Hooker et T. Thomson s. n. (lectotype designated here G-DC 00206455 image!; isolectotype CAL!, G-DC 00206454 image!, P 02025537 image!; excluded syntype Meghalaya (?) East Bengal , Griffith 4421 CAL!, G 00206467 image!) .

Piper grandipedunculum C. DC. Candollea 2: 209. 1925 syn. nov.

Type:— INDIA, Meghalaya: Khasia, Mairong, 5500ft. C. B. Clarke 40285 A (holotype CAL!).

Piper mannii C. DC. var. glabrum C. DC. Candollea 2: 205. 1925 pro parte syn. nov.

Type:— INDIA, Meghalaya, Junteah Hills, Gallatly 259 (lectotype designated here CAL! –as to upper two specimens on the right only and excluding the lower holotype of P. cornilimbum C. DC. ).

Distribution:— INDIA: Sikkim, Assam, Meghalaya, Arunachal Pradesh, Nagaland, Mizoram; BANGLADESH, BHUTAN, MYANMAR, MALAYSIA.

Note:— Casimir de Candolle (1869) described P. khasianum based on two specimens: “in mont. Khasia et Chittagong, Hook. et Thoms. n. 5” and “ India Orient, Griffith n. 4421 ”, both reportedly housed at K. Unfortunately, the Catalogue of the Kew herbarium on the web does not mention either of them and a physical search there failed as well. Instead, G-DC has these two specimens with annotations by C. de Candolle. The specimen of Hooker & Thomson (G 00206455) mentions Khasia as the locality and that of Griffith 4421 (G 00206468 & G 00206467; mounted on same sheet) has the locality as East Bengal. An examination of these reveals that the Hooker and Thomson specimen is male one whereas that of Griffith 4421 is female. Griffith 4421 is similar to Penang, G. Porter in Wallich 6644B (K 000794896 image, right hand specimen only), the lectotype of P. tumidonodosum P. K. Mukh ..(2016: 189). Both specimens share the markedly swollen nodes apart from broadly ovate-elliptic leaves with acuminate apex and pale yellow under surface. The female spikes in both are shorter than the leaves, bearing loosely placed, shortly pedicellate, ovoid fruits. Unfortunately, both the syntypes of P. khasianum at G could not be found in comparable sexes. The nodes in Hooker & Thomson 5 are not swollen, with male spikes long and flexuous.

Casimir de Candolle (1869) apparently had some confusion concerning the identity of P. khasianum and P. lonchites Miq. (1844: 331) (= P. tumidonodosum ). In fact, P. khasianum was made synonymous to P. lonchites Miq. by C. DC. (1914b), and in 1910 he annotated them as equal on some of the specimens at CAL. Two sheets of ‘ Piper (5) Khasia, 4000ft, Hook. f et Thoms. and Ind. Or.’ at CAL have annotations by C. de Candolle as ‘ P. khasianum = P. lonchites ’. Hooker (1886) also had some doubts when dealing with this species. He believed C. de Candolle used both P. hamiltonii C. DC. (1869: 360) and a part of P. nepalense Miq. (1843: 318) (= P. suipigua ) partly to describe the species. Curiously, C. de Candolle in his ‘ Clavis ’ (1923) omitted P. khasianum altogether without indication of the reason or its placement. With these facts, it is felt prudent to distinguish the two syntypes as representing two distinct entities. Piper khasianum is conceived here very narrowly, quite distinct from what has been done by C. de Candolle (1869) or Hooker (1886). Piper (5) Hooker & Thomson at G (G 00206455) is designated here as the lectotype of P. khasianum . The syntype Griffith 4421 is separated and recognised as P. tumidonodosum .

D. G. Long (1984) reduced P. curtistipes C. DC. and P. mannii C. DC. (1925: 204) as synonyms of this species. Piper curtistipes differs in its pedicellate fruits and is considered as a distinct species. Piper mannii is based upon discordant elements and is discussed later in this paper under P. phalangense C. DC. (1912: 518) . However, a part of P. mannii var. glabrum is accepted as a synonym of the present species.

Specimens at P are significantly mixed: (i) East Bengal, Griffith 4421 (P 01656221) is similar to P. suipigua ; (ii) East Bengal, Griffith 4421 female twigs (P 01656216) is similar to P. tumidonodosum ; (iii) Piper (5) Khasia, 4000 ped., J. D. H. & T.T. (P 01656218) is a male specimen similar to P. tumidonodosum ; (iv) Piper (5) Khasia, 4000 ped., J. D. H. & T.T. (P 02025559) is mixed, with the left-hand specimen similar to Piper khasianum and the right-hand specimen similar to P. tumidonodosum ; and (v) Piper (5), Khasia, 4000 ped., J. D. H. & T.T. (P 02025537) is similar to (G 00206455) and is identified as P. khasianum .