Aristolochia vallisicola (Aristolochiaceae), a new species from Peninsular Malaysia

Abstract A new species in the genus Aristolochia (Aristolochiaceae), Aristolochia vallisicola T.L.Yao, from Peninsular Malaysia is described and illustrated. Among all Peninsular Malaysian Aristolochia,itis the only species with a pinnately veined lamina and a disc-liked perianth limb. A distribution map is provided and its conservation status is assessed as Least Concern.


Introduction
Aristolochia, the largest genus in the family, consists of about 400 species. It is widely distributed throughout tropics and subtropics, but also in the warm temperate regions. Hou (1984) recognised 28 species in Malesia, 5 of which occur in Peninsular Malaysia while none of them is endemic.
Th e new species presented here was fi rst collected by a Forest Guard, Kalong (KEP) in 1929 (FMS 24048) from Ulu Kelau, Pahang. Th e specimen consists of two detached leaves and a detached infl orescence mounted on one sheet. Its vernacular name, Akar telinga berok (the pig-tail macaque's ear climber in Malay) indicates that it is a climber. After a lag of 70 years, Kiew collected a fl owering specimen (RK 4879) in the Awana waterfall area, Genting Highlands, Pahang. Th e specimen is complemented by good fi eld notes and was identifi ed as Aristolochia sp.
Recently, I was asked to identify a leaf (Kiew s.n., barcode KEP196081) of a butterfl y larva food plant collected in the Genting Tea Estate, Pahang. Th is instigated me to make a visit to the estate, which revealed that the plant is conspecifi c with the two specimens mentioned above. According to H.S. Barlow and S.K.L. Hok (pers. comm.), larvae of the butterfl y species, Parides (Atrophaneura) sycorax egertoni (Distant) 1 a member of the family Papilionidae, commonly known as the White Head Batwing (Malay name: Kepala Putih) feed on the leaves of this species. Th eir observations in the Genting Tea Estate revealed that its larvae defoliate young plants and then girdle the stem base just before they metamorphose into pupae. Th e plant manages to re-sprout later.

Taxonomy
Aristolochia vallisicola T.L.Yao, sp. nov. urn:lsid:ipni.org:names:77120982-1 http://species-id.net/wiki/Aristolochia_vallisicola Figures 1-3 Note. Th is species diff ers from all other Peninsular Malaysian Aristolochia L. species in its lamina with pinnate lateral veins, infl orescence with a long peduncle, its disc-shaped perianth limb, annulated hairy perianth mouth and 3-lobed gynostemium. Th is species is similar to Aristolochia coadunata Backer in the lanceolate or oblanceolate lamina with pinnate lateral veins but diff ers in its larger disc-shaped perianth limb, 58-65 mm diam. versus 15-30 mm diam. in A. coadunata and its longer peduncle, 15.5-17 cm long versus up to 2 cm long in A. coadunata. Th is species is also similar to Aristolochia versicolor S.M.Huang in the lanceolate or oblanceolate lamina with pinnate lateral veins but diff ers in its longer petiole, 2.5-7 cm long versus 1-2 cm long, broader leaves, at least 7.5 cm wide versus to 6.5 cm wide, and longer peduncle, 15.5-17 cm long versus 2-3(-10) cm long in A. versicolor. Th e summary and other characters comparison is presented in Table 1.
Ecology. Th is species occurs in highland valleys of lower montane forest about 1000 m altitude and often by rocky streamsides. Specimens with fl owers were collected in September and November.
Etymology. Th e species name vallisicola denotes its habitat preference for valleys.

Discussion and conclusion
Aristolochia vallisicola with disk-shaped perianth of 3 lobes which valvate in bud, annulated perianth mouth and gynostemium with 3 segments each consisting 2 stamens belongs to Isotrema (Huber 1993). Isotrema consists of ca 50 species distributed in temperate and tropical East Asia and in North and Central America. Th e new species presented here is its fi rst record in Peninsular Malaysia. Th e position of Isotrema clade within Aristolochia s.l. is confi rmed by phylogenetic studies (Kelly and González 2003;Ohi-Toma et al. 2006).
Old World Aristolochia species with a disc-shaped perianth limb are common in northern India (Hooker 1886; Karthikeyan et al. 2010) and southern China (Huang et al. 2003) while 1-lipped or 3-lobed perianth limb are prevalent in Malesian Aristolochia species (Hou 1984). Aristolochia vallisicola is the only species with a disc-liked perianth limb in Peninsular Malaysia. Apparently, it is a link between the Asian Continental element and Sumatran-Javanese Aristolochia coadunata.
Species of Aristolochia, a genus of high climber or woody lianas in Malesian forests, are not easy sighted and are very often represented by meagre herbarium specimens. Furthermore, the plants are rarely found in fl ower. In the past 15 years, 8 new species of Aristolochia were described from Th ailand (González and Poncy 1999;Hansen and Phuphatanaphong 1999;Phuphathanaphong 2006). Th is indicates that the species diversity of Aristolochia in the Old World, especially in South East Asia is still underestimated. I predict more novelties will be discovered when more specimens from this region are available for taxonomic study.