After dormancy, both pollen- and seed-cone buds resume development early in April at higher elevations on Vancouver Island. Pollen, formed the previous fall, is shed at the one-celled stage during the last half of April. Pollination occurs during a 2-week period. Pollen frequently germinates and elongates in the pollination drop within the micropyle before reaching the nucellus. Pollen tubes penetrate most of the nucellus during May and early June, then pollen-tube growth slows or stops until mid-July when the pollen tubes quickly extend to the surface of the neck cells and two large, equal-sized male gametes form. Meiosis of the megaspore mother cells occurs during April and early May. Female gametophyte development, similar to that in other members of the Cupressaceae, occurs from late May until late July. An archegonial complex forms with an average of nine archegonia. Fertilization occurs at the end of July and proembryo development begins immediately. A file of four free nuclei forms. Considerable variation exists in subsequent nuclear divisions and cell-wall formation. This may result from the long, narrow archegonia and highly variable number of archegonia. A four-tiered proembryo forms and cleavage polyembryony occurs. The embryos reach the multicellular or the massive stage with secondary suspensors by October when the cones, containing ovules which were pollinated in April, become dormant. Embryo and seed development resume the next April, 1 year after pollination, and development is usually complete in July or August. Embryo development occurs more rapidly near sea level but is complete by fall of the year after pollination at all elevations studied. Most seed is shed early in the fall, but some seed may not be shed until January. The distinction is made between immature 1-year-old and mature 2-year-old seeds and cones. Cones contained an average of 7.2 seeds, of which only 29% were filled.