Taxonomic Revision And Phylogenetic Study Of The Genus Of Impatiens In Kenya

Impatiens is one of the only two genera in the family Balsaminaceae.The other genera is the monotypic Hydrocera with only one species Hydrocera triflora(L.)Wight&Arnott.Impatiens is one of the most abundant angiosperms with more than 1000 species.It is mainly distributed in tropical Africa,Madagascar,southern India and Sri Lanka,eastern Himalayas and southeast Asia.Morphological identification of specimen in this genus is difficult,due to the species richness,the fleshy nature of the plants and the extreme fragility of the flowers.Africa being one of the main distribution centres for Impatiens has multiple subspecies,which further complicates delianation of these species.Through extensive field investigations,consulting multiple herbaria,literature review,on the morphological characteristics and phylogenetic research,preliminarily revision and phylogenetic analysis of genus Impatiens from Kenya was completed laying,a foundation for the compilation of family Balsaminaceae for the Flora of Kenya projectThis study documented the distribution records of 17 species,7 subspecies and 1 variety of Impatiens in Kenya,through examinining more than 5000 herbarium specimen from more than ten herbaria both at home and abroad,previous studies and literature researchIn this paper,41 species of Impatiens(including 16 species,3 subspecies and 1 varietiess from Kenya)were selected from the world.The nuclear gene ITS sequence and the chloroplast gene atpB-rbcL sequence were used for phylogenetic study,with Hydrocera triflora used as the outgroup.The results show that Kenyan Impatiens are mainly divided into two clades.Species in the middle clade are characterized by having 4 lateral sepals,raceme multi-flowered inflorescence,clavate or cylindrical capsule,belonging to the Tuberosae section;species in the upper clade are characterized by having 2 lateral sepals,solitary or 3-5-flowers sub-umbellate raceme inflorescence,short-fusiform capsule,belonging to the Uniflorae sectionBased on field investigations,herbarium research,and the results of morphological and phylogenetic analysis,we taxonomically revised the Impatiens species in Kenya to 17 species,4 subspecies and 1 varietas.One new record forthe country Impatiens ethiopica was reported Three names are treated as synonyms.I.nana,I.rubromaculata and I.rothii were not included due to herbarium identification errors.Morphological description,color picture,illustrations,distribution information and a key table for each Impatiens species are provided.