Taxonomic Significance And Relationship With Pollinators Of The Floral Characteristics In Epimedium

Epimedium is a perennial herb of Berberidaceae.There are about 60 species in the world,distributed intermittently in Europe and East Asia in Eurasia.China is an important geographical distribution and differentiation center of the genus,with more than 80% of the genus species distributed.Epimedium is also a traditional Chinese herbal medicine with high medicinal value.Floral characteristics play an important role for classification and phylogenetic evolution in angiosperms.Flowers are the mainly sexual reproduction organ of plants.Floral characteristics are considered to be adaptive to different pollinators,so,their diversity is extremely rich and relatively stable.Therefore,the detailed study on the sexual characteristics which has great significance in taxonomy and systematics.But for a long time,Epimedium classification has some arguement,21 kinds of Epimedium as research material collected from many places in our country and common garden cultivate in jishou university,through the observation of floral characteristics to discusses the characteristics of taxonomic significance;an pollination ecology observation experiment was conducted of Epimedium myrianthum and Epimedium epsteinii in Tianping Mountain,Badagongshan Nature Reserve,Hunan Province from April to May 2021 to study the relationship between different floral characteristics and the adaptability of pollinators.The results are as follows:(1)The flower morphology of 21 common garden cultivated plants of Epimedium was observed,of which 10 species belonged to the Large-flowered type and 11 species belonged to the Small-flowered type.The flowers of Epimedium are hermaphroditic,panicle or raceme,diameter of flowers was 5.14-43.46 mm,and the inner sepals like a petal and rich in color.Petal 4,specialized in spur(except for E.ecalcaratum),in a variety of colors.According to the comparison of the spur length and the inner sepal length,it can be divided into three types:(1)without spur;the spur is longer than the inner sepal;(3)the spur is shorter than the inner sepal.(2)To investigate whether the floral characteristics of Epimedium has taxonomic significance.An average floral longevity is 3.61 ± 0.22 d.The characteristics of flowers between species are significantly different,and the results of principal component analysis show that the information load of traits such as flower diameter,inner sepal length,anther length and ovule number is the largest,which plays a major role in the classification of this genus.The 21 species of Epimedium are classified according to the floral characteristics,which can be divided into four groups: Clade 1 the flowers are small,the filament is obviously elongated,up to 10 mm,and the spur is subulate.Clade2 the flowers are small,and the petals are not specialized to form a spur.Clade 3 the flowers are small,the petals are shorter than the inner sepals,and spur was saccular or pocket.Clade 4 the flowers are larger,the petals are longer than the inner sepals,spur was long.(3)In order to explore the relationship between the different flower characteristics of Epimedium with the pollinator taxon and their reproductive success,a pollination ecology observation experiment was conducted of Epimedium myrianthum and Epimedium epsteinii in Tianping Mountain,Badagongshan Nature Reserve,Hunan Province.The results showed that the flower characteristics of the two kinds of Epimedium were very different,the inner sepals of Epimedium myrianthum were white,the spur was yellow,and the inner sepals were significantly longer than the spur,which belonged to the small flower group.the outer sepals and spur of the Epimedium epsteinii were lilacs,and the spur was drilled and significantly longer than the inner sepals,which belonged to the large flower group.Epimedium myrianthum and Epimedium epsteinii distribute in the same area,with overlapping flowering periods,but peaks of flowering periods are staggered.The floral longevity of Epimedium myrianthum and Epimedium epsteinii were 3.5 ± 0.21 d and 3.1 ± 0.22 d,respectively.Both Epimedium are female-first ripe,pollen viability of the two species decreased gradually with flower opening.Artificial pollination experiments showed that Epimedium myrianthum and Epimedium epsteinii were self-incompatible and cross-compatible,and pollination was dependent on pollinators,there was a certain degree of pollination restriction in the natural state of Epimedium myrianthum.The effective pollinator of Epimedium myrianthum are the smaller Halictus,Apis,Megachile and Syrphus all have a degree of pollen theft.Epimedium epsteinii effective pollinator is the larger Bombus trifasciatus.The sexual reproduction characteristics of Epimedium plants based on common garden experiments have certain taxonomic significance,which can provide a certain basis for the classification of Epimedium group.The different flower morphology of Epimedium reflects selective adaptation to different pollinators or pollinator functional groups,different flower characteristics adapts to different pollinators.