Photograph by Ron Oldfield, Macquarie University, See http://dx.doi.org/10.1093/aob/mcs295
The image shows sporophytes and calyptras of Funaria hygrometrica, a water moss (photograph by Ron Oldfield, Macquarie University). The calyptra is a gametophytic tissue that covers the tip of the elongating sporophyte. A young sporophyte with an intact calyptra appears in the lower left corner, whilst other sporophytes are in the process of shedding their calyptras or have already shed them. The calyptra is proposed to function, in part, as a maternal constraint on capsule expansion, as an expression of parent–offspring conflict.
See Haig http://dx.doi.org/10.1093/aob/mcs295 (subscription link – free after April 2014)