Impatiens nicolsoniana Gogoi & Arisdason, 2016

Impatiens nicolsoniana Gogoi & Arisdason View in CoL , nom. nov.

Replaced synonym: Impatiens mannii C.B. Clarke ex Hooker filius (1906: 27), nom. illeg., non I. mannii Hooker filius (1861: 7).

TYPE:— INDIA. Assam: Makum Forest , Lakhimpur, September 1890, Gustav Mann s.n. ( K000694773 , image!) . Fig. 1 View FIGURE 1 .

Etymology:—The specific epithet honours Dr. Dan H. Nicolson, Curator, National Herbarium of the Smithsonian Institution, Washington, D.C., USA (who passed away on June 2, 2016, after a long struggle with Alzheimer’s disease), for his invaluable contributions to the International Code of Botanical Nomenclature.

Notes:— Impatiens mannii C.B. Clarke ex Hook.f. (here renamed as Impatiens nicolsoniana ) is an endemic species confined to Arunachal Pradesh and Assam in north-east India ( Vivekananthan et al. 1997), whereas, the African endemic is confined to south-west Cameroon, Fernando Po (Bioko), Gabon, east Zaire and west Uganda (Grey-Wilson 1980).

Furthermore, these two species are quite distinct from each other morphologically. The Indian plant differs from the African plant by being about 30 cm high annual (vs. 1.5 m high straggling perennial herb), leaves alternate (vs. spiral), flowers solitary and axillary in position (vs. 2–12 in axillary fascicles), petals brick red to red (vs. white, pink or violet, or reddish), lower sepals navicular with gradually constricted spur, and basal lobe of lateral united petals prominent (vs. navicular with abruptly constricted spur, and basal lobe of lateral united petals inconspicuous).

During the present study efforts were taken to locate the type specimens of both names at K. The type specimen (Gustav Mann s.n., K000694773, image!) of I. mannii C.B. Clarke ex Hook. f. was traced among I. cuspidifera Hooker filius (1906: 27), and in fact, it is the only existing original material of the name. Grey-Wilson (1980) in his book, Impatiens of Africa, indicated a specimen at K ( Fernando Po, Clarence Peak, 4000’, G. Mann s.n.), collected by Gustav Mann as the holotype of I. mannii Hook.f. However , while searching for the type at K, a specimen ( Fernando Po, 4000’, December 1860, Gustav Mann 585, K000419414, image!; Fig. 2 View FIGURE 2 ) matching exactly with the type details given in the protologue was located.