Figure 2

Ginkgo male and female short shoots. (A) The fertile female structure (megasporangia) has just emerged from the bud. Two ovules set on a green stalk are visible. Young, unfurled leaves, which have also emerged have extended above the megasporangia. The bracts, which originally enclosed the bud, are now completely opened below the leaves and megasporangia (B) Scanning EM of an ovule, which is completely enclosed by an integument. (C) A longitudinal cross section of the megasporangia reveals the integument enclosing the nucellus. (D) The male reproductive structure is a cluster of microsporangia. In the center of the bud are partly emerged leaves (E) Scanning EM shows two microsporangial lobes containing ripening pollen sacks attached to a stalk. (F) Longitudinal cross section shows a large mucilage containing cavity juxtaposed from the microsporangia filled with immature pollen. C integument; N, nucellus; I, microsporngia; L, mucilage cavity. O, ovule