New observations on a rare endobiotic green alga, Stomatochroon lagerheimii, from a tropical area in China

Abstract

Stomatochroon lagerheimii is a rare endobiotic green alga that lives in the stomatal chambers of the leaves from tropical vascular plants. The only report, to date, on this species was from Sumatra, Indonesia, by Palm in 1934. For this study, specimens were collected from a tropical rain forest inYunan, south west China, and each section of the thallus was measured using these Chinese specimens since the dimensions for each part were not given in Palm's original description. Using LM and SEM, this study has discovered further important characteristics about S. lagerheimii. Notably, that the external part of S. lagerheimii can be deep orange - red as well as deep purple, the sporangia wall is reticulate and the setae are the first structures to arise from the basal cell of a germling. The host plants, originally from Indonesia and China, are from the genus, Clerodendrum (Verbenaceae), which suggests that this alga is an endobiotic parasitic species that exhibits host specificity.