Fig. 4

Ovule development of flowers of Cylindropuntia wolfii. (A) Ovule in male flower at pre-anthesis, with long funicle (FU) and integuments (external (EI) and internal (II)) developing with a Megaspore Mother Cell (MC). (B) Ovule of male flower in late pre-anthesis showing the collapse of the megagametophyte (MG). (C) Aborted ovule in male flower completely collapses in male flowers, at maturity only cellular debris are observed. (D) Ovule of female flower in early pre-anthesis, with a long funicle (FU) and integuments (external (EI) and internal (II)) developing with an archesporial cell (AC). (E) Ovule of female flower in early pre-anthesis showing the formation of the megagametophyte (MG). (F) Fully mature ovule of female flower in early pre-anthesis showing well developed megagametophyte and tannin (TN) deposits