Carotenoids begin to form during the 1st 6 h of spore germination in P. commune Hedw., when spore swelling and germ tube protrusion are taking place. Thus, carotenoid synthesis commences before the before the 1st chloroplast replication. The 72 h old sporelings contained carotenes (292%), violaxanthin (789%), lutein + antheraxanthin (379%), neoxanthin (334%) and zeaxanthin (689%), compared with the contents of ungerminated spores. The ratio of carotenes to xanthophylls changes during germination. The ungerminated spores contain 32% carotenes and 68% xanthophylls while 72 h old sporlings contain 23% carotenes and 77% xanthophylls. During germination the amount of carotenoids per chloroplast decreases.