Male Flowers and Relationship between Plant Size and Sex Expression in Herbaria of Nomocharis Species(Liliaceae)

Despite the general rarity of female-sterile reproductive systems,male flowers are widespread in Liliaceae.Nomocharis( Liliaceae) consists of ca. seven species which have been traditionally classified as hermaphrodite. However,our preliminary investigation suggested that male flowers may occur frequently in this genus. We got data of the flower sex phenotypes,flower size,plant height and altitude by observing and measuring specimens of Nomocharis from several herbaria( PE,KUN,HITBC CDBI) in China,and then used them to determine the sex distribution and to analyze the relationships between plant size and flower size,sex expression. We found that male flowers occurred in all six studied Nomocharis species and different combinations of hermaphroditic and male flowers at plant level resulted in complex sex expression. Of four further studied species,male plants were significantly smaller thanplants with hermaphroditic flowers in three species. Plant height,which was not related to altitude,but not sex phenotype has significant effects on flower size. The number of total flowers and hermaphroditic flowers per plant increased with plant size. However,the number of male flowers was independently of size. Our study suggested resources availability( i. e. plant size) determined the sex phenotypes of individuals. We highlighted the occurrence of male flowers in genus Nomocharis and suggested further field studies are absolutely necessary. Furthermore,this study provides a case study to better use herbarium specimens as prerequisites for field researches of floral sexual diversity.