Induced vivipary in the sedge Cyperus virens and the transmission of the fungus Balansia cyperi (Clavicipitaceae)

Abstract

Individuals of the sedge Cyperus virens Mich. are frequently infected by the systemic fungus Balansia cyperi Edg. (Clavicipitaceae). Developing inflorescences of infected plants are enveloped by fungal hyphae, preventing their expansion. Viviparous plantlets are sometimes produced on the aborted inflorescences of infected plants and the plantlets themselves are infected by B. cyperi. To estimate the extent of infection and vivipary, five populations of C. virens from the southwestern coast of Louisiana were sampled along randomly located line transects. Approximately one-half of over 500 sampled plants were infected by B. cyperi and about 30% of the infected plants were viviparous. There were significant differences between transects within populations and among populations in the percentage of infected plants and of infected, viviparous plants. Viviparous, infected plants were, on average, four times as big as uninfected plants and three times as big as nonviviparous, infected plants. Induced vivipary represents a mechanism of vegetative reproduction where host plant and fungus are dispersed simultaneously in the same propagule.