The pollination biology of Camellia oleifera,an important plant producing edible oil,was studied during 2007 and 2008 in Hunan Province,central south China.It blooms during October to January and the flowering period usually lasts about 20 days for single plant and 4-5 days for single flower.The volume of nectar,containing sugar ( ( 23.13±1.03) % ) and 17 kinds of amino acid ( 1.73% ) ,is ( 145.40±24.89) μL per flower ( n=30) .Andrena camellia and Colletes gigas ( Hymenoptera:Apoidea) are the effective pollinators and the pollination efficiency of the A.camellia is higher than that of the Colletes gigas.Flies and butterflies are casual visitors.Breeding experiments showed that C.oleifera is primarily self-incompatible with a significant difference in reproductive success between self-pollination and cross-pollination.There is no apomixis and autonomous self-pollination,so the pollination,fruiting and seeding of this species depends on pollinators.The result of hand cross-pollination of C.oleifera showed that when pollen is supplemented,seed number increases but fruit production remains the same.The nectar characteristics that we found in C.oleifera,i.e.high volume nectar and dilute sugar content,suggest the bird-pollination syndrome but the phylogenetic position of C.oleifera in the genus Camellia does not allow us to interpret how this syndrome could have evolved in this species.

Camellia oleifera is one of the most important woody oil plants,which blooms from late autumn to winter.The study on pollination characteristics of Camellia oleifera is one of the keys to solve the low fruit rate.In this paper,pollen activity and viability,amount of pollen,nectar volume and sugar concentration,stigmas receptivity and pollen/ovule ratio(P/O) were studied.The results demonstrated that the highest pollen viability was 71.0%±0.056% after eight hours of flowering;rate of pollen fertility was 93.97%±1.62%(n=30);stigma receptivity reached the highest rate on the second day after flowering;nectar volume of each flower was 421.2±14.0 μL(n=30),with a sugar concentration of 29.12%±0.94%;P/O was 17675.08±302.11(n=20),which revealed that Camellia oleifera was obligate xenogamy.

Two species,namely Exochorda racemosa and Lysimachia klattiana,are reported as new records to Hunan Province based on a research on the seed plants of Shiniuzhai and its surrounding Danxia landform area,where there are 687 species(including some varieties) of wild seed plants belonging to 422 genera and 136 families.The statistics and results obtained from their intensive analyses at different levels are given in this paper,which show,from a view of their genera distribution pattern,that the main geographical elements are Pantropic(22.22%),North Temperate(17.99%) and E.Asia(16.93%);and that the flora of Shiniuzhai takes its characteristics of a strong tropical nature,vigorous xerophytes and liana,thus affected by the Danxia landform.