Phaeoceros perpusillus var. scabrellus A plants in natural habitat B dorsal view of thallus showing marginal tubers (arrow) C ventral view of thallus showing ventral tubers (arrows) D cross-section of thallus showing the large dark lump of Nostoc colony (NC = Nostoc colony) E dorsal epidermal cells of thallus showing a single chloroplast with pyrenoid (arrows) per cell F spores and pseudoelaters. Photos by O. Suwanmala (A from S. Chantanaorrapint & O. Suwanmala 4116 B–F from S. Chantanaorrapint & O. Suwanmala 4077).