NOTES RELATING TO THE FLORA OF BHUTAN: XXX. GENTIANACEAE

Two new species of gentian, Gentiana wangchukii E. Aitken & D.G. Long sp. nov., endemic to Bhutan, and Gentianella urnigera E. Aitken & D.G. Long sp. nov., from East Nepal, Sikkim, Central and Northern Bhutan and Yunnan, China, are described. Their generic placement and differences from allied species are discussed. The new combination Lomatogonium himalayense f Klotzsch) E. Aitken comb. nov. is made and this name is applied to plants previously ascribed to L. carinthiacum (Wulfen) Reichenbach from the East Himalaya; the basionym Pleurogyne himalayensis Klotzsch is lectotypified and epitypified. The genus Tripterospermum is reviewed in the Flora of Bhutan area and two species are recognized: T. volubile (D. Don) Hara and T. nigro-baccatum Hara. Within T. volubile, two subspecies are recognized: subsp. volubile and subsp. longipes E. Aitken & D.G. Long subsp. nov. T. luteoviride (C.B. Clarke) Murata, in the past treated as a distinct species, is placed in synonymy of subsp. volubile.

Similar to G. cuneibarba H. Smith in having thick white hairs in the corolla throat, but is a much smaller plant with more compact habit, + glabrous stems, acuminate corolla lobes and bifid plicae.
These specimens had been annotated as Gentiana pogolema and G faucibarbata by Harry Smith, but these two names were never published. The two specimens were later (1987) re-determined as G. cuneibarba H. Smith by T.N. Ho as part of the revision for Flora of China. However, in comparison with the type specimen of G cuneibarba and that of another related species, G. faucipilosa H. Smith, both from Yunnan, several differences were found, as summarized in Table 1.
The species name has been chosen to commemorate the late King of Bhutan, H.R.H. Jigme Dorji Wangchuk, amongst whose most notable achievements was the recognition of the richness of Bhutan's fauna and flora and the promotion of their protection. This species was first noticed among specimens of Gentianella stellariifolia (Forbes & Hemsley) H. Smith at Edinburgh (E), Kew (K) and The Natural History Museum, London (BM). Some of the smaller specimens from Bhutan, and one from Yunnan, had been annotated as Gentianella divaricata by H. Smith, but this name was never published. Ludlow, Sherriff' & Hicks 21135 from NE Bhutan is a much larger plant which has the same characteristics as the typical form. This specimen is for the present included in the description, with the larger measurements in parentheses, although it could possibly be treated as a variety if further material were available for a more extensive study.
The specific epithet derives from the distinctly urn-shaped calyces. There are distinct differences between the new species and G. stellariifolia, which are summarized in Table 2.
Some authors have subdivided Gentianella Moench into smaller segregate genera, e.g. Ho & Wu (1988) in China and Omer & Qaiser (1992) in Pakistan. Following their narrower generic limits, this species would have been placed under Comastoma Toyokuni (as is G. stellariifolia) on account of its fimbriate corolla throat. As discussed by Aitken & Long (1994) in describing Gentianella griersonii, there is a strong case for retaining Gentianella in the broadest sense, as generic limits throughout Gentianaceae require a comprehensive worldwide review.

LOMATOGONIUM
Lomatogonium carinthiacum (Wulfen) Reichenbach was first described from Europe (Wulfen, 1781) in the genus Swertia, and the name has frequently been applied (e.g. Chater, 1982;Garg, 1987;Liu & Ho, 1992) to specimens from the Himalaya. While some plants from the NW Himalaya appear to be conspecific with the European plant, others from this area, together with the E Himalayan plants, are clearly different. These differ in being much larger, more branched above, with larger leaves and often longer, narrower calyx lobes. In these characters they agree with the plant described and illustrated by Klotzsch (1862) as Pleurogyne himalayensis.
It has not been possible to locate any type specimens of Klotzsch's plant (Himalaya, Hoffmeister). The illustration (t. 68) appears to be the only element in the protologue available for typification. Fortunately, it is of high quality and demonstrates that this plant clearly belongs to the genus Lomatogonium in characters such as the decurrent stigma. The necessary new combination is made below. Under the new Tokyo edition of the International Code of Botanical Nomenclature (ICBN) (Greuter et al., 1994) it is permissible to supplement such a lectotypification by an interpretive specimen ('epitype'), which serves to unequivocally stabilise the application of the basionym in question. Because Lomatogonium includes several critical species, such a step is advisable. The epitype selected below closely matches the protologue and the lectotype illustration, and originates from the NW Himalaya whence the original material was almost certainly collected by Hoffmeister.

Review of Tripterospermum in the East Himalaya
Discrimination of the species of Tripterospermum in the East Himalaya was found to be difficult (especially for non-fruiting material), and the extensive material available did not fit into the three species accepted for the region in the revision of Murata (1989). This prompted a more detailed study of the specimens and particularly types, and the treatments of Murata (1989), Hara (1967) and earlier workers.
Murata (1989) recognized three species from the area of the Flora of Bhutan: T. volubile (D. Don) Hara, T. nigrobaccatum Hara and T. luteoviride (C.B. Clarke) Murata. T. nigrobaccatum we agree is a distinctive species (Table 3) with its calyx unwinged and a short black berry, whereas the other two red-berried taxa are problematic, in that Hara (1965,1967) had united them both under the name T. volubile. The current study of available material suggested that there were nevertheless three distinct entities (Table 3) in Darjeeling, Sikkim and Bhutan, but the two red-berried taxa did not fit Murata's circumscriptions of T. volubile and T. luteoviride. Sealy (1949) selected a lectotype for Gentiana volubilis D. Don: 'E. Napalia, anno 1818, Wallich s.n.' (BM). Significantly this type specimen had also been annotated by C.B. Clarke as Crawfurdia luteoviridis, supporting the view of Sealy (1949) that C. luteoviridis is not a distinct species, but a synonym of T volubile. Clarke (1875) in describing C. luteoviridis did not specify a type but indicated that he included a wide range of material 'In omni Himalaya a Bhotan at Kemaoon ad 5000-10,000 ped. alt. frequens'. In K and BM there are at least 15 specimens annotated C. luteoviridis by Clarke, including the Wallich specimen mentioned above. All of these have been redetermined by Murata as Tripterospermum volubile. This suggests that Murata's concept of T. luteoviride might not be in accordance with Clarke's.  2.5-5.5(-8) x 0.6-1.5cm ribbed, 5-6mm 5-8x0.5-lmm 16 26mm 2-4 x 3 4mm, creamy white or pale greenish streaked purple 3-5(-9)mm 1.5-3(-4)mm 9-12mm black, 10-15 x 5-6mm 6-10mm; enclosed by corolla or protruding slightly E Nepal, Darjeeling, Sikkim, Bhutan 2440-3080m Hara (1965 had clearly agreed with Sealy that the two were synonymous, and had (Hara, 1965) in fact lectotypified the name C. luteoviridis by the following specimen: 'Darjeeling, 7300ft. (C.B. Clarke, no. 26998, Aug. 15, 1875) in Herb. Kew\ Murata presumably overlooked Hara's lectotypification, as he (1989: 281-282) made no reference to it and selected a different lectotype (Wallich 4369), stating 'I choose Wallich 4369 as the lectotype of Craw fur dia luteoviridis C.B. Clarke, because only this specimen is evidently included in the original description'. In fact, this specimen was not cited in the protologue, nor was it annotated as C. luteoviridis by Clarke.
This is an unnecessary typification. Under Art. 9.13 of 1CBN (Greuter et al.. 1994) a choice of lectotype may be superseded if it can be shown that it was not part of the original material used by the author in preparing the protologue, and that original material is available. There is no evidence that Clarke used the specimen selected by Murata, yet there are at least 15 other specimens which he did! Hara's lectotype, on the other hand, (although not found by us at Kew in 1994) was collected by and presumably annotated by Clarke and must be upheld as lectotype.
Murata (1989) also commented on Clarke's description of the fruit of C. luteoviridis: 'Capsula baccata, oblonga, stipitem ter superans' and suggested that this agreed with Murata's 'Species C (i.e. T. luteoviride sensu Murata non Clarke). However, many of the specimens annotated by Clarke as C. luteoviridis have a stipe 7-10mm and a fruit up to 28mm and in our opinion do not significantly discord with the protologue. Furthermore, our studies of Wallich 4369 (K-W, K) suggest that it is the same taxon as Gentiana volubilis.
Murata (1989) placed great emphasis on the relative lengths of mature fruit and the stalk of the fruit in relation to the persistent calyx and corolla. We concur with this, but note that in specimens in flower or young fruit, reliance on this character alone can be misleading, as the fruit stipe is not fully elongated. Murata distinguished T. volubile as having a fruit 'Type C (i.e. with a very long stipe 'distinctly longer than calyx-tube') and T. luteoviride as having a fruit 'Type E' with a stipe shorter than (occasionally as long as) the calyx tube. Our interpretation of the lectotype of Gentiana volubilis is that it is an immature specimen of a taxon with a stipe intermediate in length between Murata's 'Type C and 'Type E'. This taxon is Tripterospermum volubile as circumscribed by Sealy (1949) and Hara (1967), but excluding some plants from Darjeeling, e.g. that illustrated by Hooker (1881). In T. volubile the ripe fruit stipe always + equals the fruiting calyx, and the fruit itself is only partly (up to 50%) exserted from the persistent corolla. Both Hara and Murata identified numerous such 'intermediate' specimens as T. volubile. Thus we conclude, as did Sealy and Hara, that C. luteoviridis is a synonym of Tripterospermum volubile.
However, a third taxon exists for which there is no name, but was included within T. volubile by Murata. This is the plant illustrated by Hooker (1881) as Crawfurdia luteoviridis, which differs in a number of characters from typical T. volubile. Its fruit is exactly that of 'Type C of Murata (1989), i.e. the ripe stipe is much longer than the fruiting calyx, and the fruit itself is almost totally exserted from the corolla.
Murata's fig. 16A (unfortunately without indication of specimen on which it was based) is of this taxon, clearly showing the exserted capsule. This taxon (which is described here as Tripterospermum volubile subsp. longipes) can be distinguished in addition (Table 3) by its longer filaments and style which is bifid to the middle. Even immature specimens of T. volubile (including T. luteoviride) display these two features, having shorter filaments and a long simple style which is not branched below the middle.
Differs from T. volubile subsp. volubile in having a longer calyx and corolla tube and longer filaments. Basal part of style shorter and apex more deeply bifid. Stipe on ripe fruit elongating so that fruit protrudes almost completely from corolla. Much narrower geographical distribution than subsp. volubile.