The living species of the genus Retrophyllum C.N. Page (Podocarpaceae) are revised. A key to the six species recognised is given. Retrophyllum filicifolium (N.E.Gray) R.R.Mill comb. nov. from New Guinea and the Moluccas is recognised as a species distinct from R. vitiense (Seemann) C.N. Page, which is restricted to material from Fiji and the Solomon Islands. Additional characters are given by which to separate Retrophyllum piresii (Silba) C.N. Page (Brazil) from R. rospigliosii (Pilg.) C.N. Page (Andes). The six species fall into three species-pairs that differ in reproductive characters: one pair in Papuasia and Melanesia, a second on New Caledonia and a third in South America. In the New Caledonian species-pair, the adult leaves are flattened in four ranks with only minimal heterofacial twisting, whereas in the species-pair inhabiting Fiji, New Guinea and neighbouring areas, as well as the pair inhabiting South America, the adult leaves are arranged in two ranks with significant heterofacial twisting. The names Podocarpus filicifolius N.E.Gray and Nageia minor Carrière, respectively the basionyms of Retrophyllum filicifolium and R. minus, are lectotypified, and the typification of Nageia minor comprehensively discussed in an appendix. Adult female epitypes are additionally designated for Podocarpus filicifolius, which was originally based on juvenile foliage of Retrophyllum mixed with a detached seed of Nageia wallichiana, and for Nageia minor, which Carrière described on the basis of sterile material. Two other appendices provide a list of accepted names and synonyms, and a list of exsiccatae. Illustrations and distribution maps are provided for each species.

Although it has been speculated that seeds of the gymnosperm family Podocarpaceae have an underdeveloped embryo, no detailed studies have been done to definitively answer this question. Our purpose was to determine if embryos in seeds of two species of Podocarpaceae, Podocarpus costalis and Nageia nagi, from Taiwan are underdeveloped and to examine the kind of dormancy the seeds have. Embryos in fresh seeds of P. costalis were 4.6 ± 0.5 mm long, and they increased in length by about 54% before radicle emergence (germination), demonstrating that the embryo is underdeveloped at seed maturity. Seeds germinated to >90% at 30/20, 25/15 and 25°C in light in ≤ 4 weeks, without any cold stratification pretreatment. Thus, seeds of P. costalis have morphological dormancy (MD). Embryos in fresh seeds of N. nagi were 7.4 ± 0.8 mm long and they increased in length by about 39% before radicle emergence (germination) occurred, indicating that the embryo is underdeveloped at seed maturity. Seeds germinated to < 25% at 30/20 and 25°C in light in 4 weeks but to >90% at the same temperatures in 12 weeks. Thus, most seeds of N. nagi have morphophysiological dormancy (MPD). Although underdeveloped embryos are considered to be a primitive condition in seed plants, they also occur in the most advanced orders. The occurrence of underdeveloped embryos in Podocarpaceae documents that they are not restricted to a basal clade in gymnosperms.

Thirty-three conifer species are currently recorded from Vietnam, Laos and Cambodia. All species are recorded from Vietnam but only six have been recorded from Cambodia and nine from Laos. Recent botanical surveys have recorded one additional species from Cambodia and seven from Laos. New distributions within those countries have also been recorded. This paper discusses those records.