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Background and Aims The three relict genera Pherosphaera, Microcachrys and Saxegothaea in Podocarpaceae produce quite distinct seed cone types in comparison with other genera and do not form a clade along with Acmopyle. The detailed seed cone morpho-anatomy of these three relict genera and affinities with other podocarps are poorly known. This study aims to understand the seed cone morpho-anatomy and affinities among these three disjunct relict genera and with other podocarps. Methods We comparatively analysed the seed cone morpho-anatomical traits of the three podocarps genera and used ancestral state reconstruction to understand the evolution of these traits. Key Results We described the seed cone morpho-anatomical structures of the three relict genera in detail. The three genera produce aggregated multiovulate cones. Both Microcachrys and Saxegothaea have an asymmetrical free cup-like epimatium. Both species of Pherosphaera lack an epimatium. The ancestral state reconstruction implies that the presence of an epimatium is an ancestral trait in podocarps and is independently lost in Pherosphaera and Phyllocladus. The seed cones are fleshy in Microcachrys and non-fleshy in Saxegothaea and Pherosphaera. The seed cone macrofossils of both extinct and living podocarps also show the presence of an epimatium and fleshiness in podocarps. Conclusions Altogether, the morpho-anatomy suggests that Pherosphaera, Microcachrys and Saxegothaea present affinities with each other and other podocarps, but the reconstruction of the ancestral seed cone in Podcarpaceae is quite complex due to multiple convergent evolutions of several structures. These structures (e.g. epimatium, aril and receptaculum) are of low taxonomic value but of great evolutionary and ecological significance, and are responsive adaptations to ever-changing environmental conditions.

†Background and Aims Globally, conifer dominance is restricted to nutient-poor habitats in colder, drier or waterlogged environments, probably due to competition with angiosperms. Analysis of canopy structure is important for understanding the mechanism of plant coexistence in relation to competition for light. Most conifers are shade intolerant, and often have narrow, deep, conical crowns. In this study it is predicted that conifer-admixed forests have less distinct upper canopies and more undulating canopy surfaces than angiosperm-dominated forests. †Methods By using a ground-based, portable light detection and ranging (LIDAR) system, canopy structure was quantified for old-growth evergreen rainforests with varying dominance of conifers along altitudinal gradients (200‐3100 m a.s.l.) on tropical and sub-tropical mountains (Mount Kinabalu, Malaysian Borneo and Yakushima Island, Japan) that have different conifer floras. †Key Results Conifers dominated at higher elevations on both mountains (Podocarpaceae and Araucariaceae on Kinabalu and Cupressaceae and Pinaceae on Yakushima), but conifer dominance also varied with soil/substrate conditions on Kinabalu. Conifer dominance was associated with the existence of large-diameter conifers. Forests with higher conifer dominance showed a canopy height profile (CHP) more skewed towards the understorey on both Kinabalu and Yakushima. In contrast, angiosperm-dominated forests had a CHP skewed towards upper canopy, except for lowland dipterocarp forests and a sub-alpine scrub dominated by small-leaved Leptospermum recurvum (Myrtaceae) on Kinabalu. Forests with a less dense upper canopy had more undulating outer canopy surfaces. Mixed conifer‐ angiosperm forests on Yakushima and dipterocarp forests on Kinabalu showed similar canopy structures. †Conclusions The results generally supported the prediction, suggesting that lower growth of angiosperm trees (except L. recurvum on Kinabalu) in cold and nutrient-poor environments results in a sparser upper canopy, which allows shade-intolerant conifers to co-occur with angiosperm trees either as emergents or as codominants in the open canopy.

DNA sequences have been mapped to the chromosomes of Podocarpus species from New Zealand and Australia by fluorescent in situ hybridization. Unlike other conifers, these species show only one pair of major sites of 45S rDNA genes, and two additional minor sites were seen in the Australian P. lawrencei. Unusually, 45S sequences collocalize to the same chromosomal region as the 5S rDNA. The telomere probe (TTTAGGG)n hybridizes to the ends of all chromosomes as well as to a large number of small sites distributed along the length of all chromosomes. Two other simple sequence repeats, (AAC)5 and (GATA)4, show a diffuse pattern of hybridization sites distributed along chromosomes. Southern blots using a variety of probes obtained from the reverse transcriptase of retroelements (gypsy, copia and LINE) from P. totara, P. nivalis and Dacrycarpus dacrydioides show that these retroelements are abundant and widespread in Podocarpaceae and also in others conifers. Some retroelements such as copia pPonty3 and gypsy pPot1li are more abundant in the genome of Picea abies and Ginkgo biloba than in the species from which they were amplified.

The developmental morphology and anatomy of the female cones of Acmopyle pancheri (Brongn. & Gris) Pilg. (Podocarpaceae) are described and illustrated, based on observations, histology, scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR) imaging. Ovulate development is typically podocarpaceous. Ovules are unitegmic, and horizontal or inclined upwards throughout ontogeny; the pollination drop is inverted because of the declinate micropyle. Ontogeny of the epimatium-ovule complex is acropetal, the epimatium developing first. A terminal, distal sterile bract creates a pollen-scavenging area. During development, the whole cone re-orientates through some 270°, and the seed realigns approx. 60° with respect to the receptacle axis. The ‘receptacle’ or podocarpium supporting the seed is formed by gradual fusion of initially free bracts. The structures adnate to these bracts represent homologues of ovuliferous scales; they bear vestigial epimatia which may develop into supernumerary ovules or non-functional epimatia. Thus, female cones of A. pancheri are vestigially multi-ovulate. NMR imaging effectively and non-invasively revealed the three-dimensional arrangement of vascular bundles and resin canals in the cones.

The pollination mechanisms of Acmopyle pancheri (Brongn. & Gris) Pilg. and Phyllocladus hypophyllus Hook.f. were investigated by conventional microscopical techniques and by nuclear magnetic resonance (NMR) imaging. Dissimilarities include the orientation of the ovule and type of pollen; Phyllocladus has erect ovules and wettable pollen with vestigial sacci, whereas Acmopyle has more-or-less erect ovules and non-wettable, functionally saccate pollen. Similarities include the mode of formation of the pollination drop and its response upon pollination. In both genera, pollination triggers pollination drop retraction and drop secretion ceases. Neither NMR imaging nor conventional histology of Phyllocladus ovules revealed any specific tissue beneath the ovule which could be responsible for pollination drop retraction. It is more likely, therefore, that the drop is channelled into the vascular supply or the apoplast. These findings invalidate the taxonomic value of the pollination mechanism as a suite of characters traditionally used to separate Phyllocladaceae from Podocarpaceae.

To analyse the status and phylogeny of the genus Phyllocladus, seeds of all seven species of the genus were studied. The complex of features of the Phyllocladus reproductive system point to the isolated position of the genus within the conifers. Relations with Podocarpaceae s. l., Taxaceae s. l. and Cephalotaxaceae appeared to be remote because a complex of features clearly distinguishes Phyllocladus from the afore-mentioned taxa. We find it advisable to circumscribe the family Phyllocladaceae as Bessey (1907) did, and place it into the order Taxales Knobl. in Warming (1890). From investigations of the seeds it appears the genus Phyllocladus consists of seven species, forming five groups. There is a significant tendency for transformation of the female reproductive structures within the generic boundaries of Phyllocladus —seeds, originally solitary, tending to aggregate in various kinds of compact clusters.

The pollination mechanism of most genera of the Podocarpaceae involves inverted ovules, a pollination drop and bisaccate pollen grains. Saccate grains have sometimes been referred to as 'non-wettable' due to their buoyant properties, while non-saccate pollen grains have been described as 'wettable'. The hydrodynamic properties of saccate pollen grains of seven podocarp species in five genera, Dacrydium Sol. ex G. Forst., Dacrycarpus (Endl.) de Laub., Manoao Molloy, Podocarpus L'Her. ex Pers. and Prumnopitys Phil. have been tested in water, together with saccate and non-saccate pollen of four other conifer genera, Cedrus Trew (Pinaceae), Cephalotaxus Siebold & Zucc. ex Endl. (Cephalotaxaceae), Cupressus L. (Cupressaceae) and Phyllocladus Rich. ex Mirb. (Phyllocladaceae), and spores of three fern species and one lycopod species. All four spore types studied were non-wettable, whereas the bisaccate and trisaccate pollen types, like all other conifer pollen types, were wettable, enabling the grains to cross the surface tension barrier of water. Once past this barrier, grain behaviour was governed by presence or absence of sacci. Non-saccate and vestigially saccate grains sank, whereas saccate grains behaved like air bubbles, floating up to the highest point. In addition, the grains were observed to float in water with sacci uppermost, consistent with the suggestion that distally placed sacci serve to orientate the germinal furrow of the pollen grain towards the nucellus of an inverted ovule. Observations of pollen grains in the pollen chambers of naturally pollinated Prumnopitvs ovules confirmed this. The combination of buoyancy and wettability in saccate pollen has implications for the efficiency of the typical podocarp pollination mechanism.

PLANTS radicicola which penetrates are capable into the of root-hairs producing and root-nodules subsequently when the Bacillus cortical r icola enetrates in the root-hairs nd subsequ ntl the corti al cells of the root may be placed in two classes those which belong to the Natural Order Leguminosae and those which do not. All .these structures have been shown by several investigators to be actively concerned with assimilation of nitrogen. The bacteria utilize the free nitrogen of the atmosphere, and since the plants associated with them can live in very poor soil they produce nitrogenous material which can be assimilated by the plant. This symbiotic association is characteristic of the two gymnospermous families Cycadaceae and Podocarpaceae, the dicotyledonous families Elaeagnaceae and Myricaceae, and the genera Almts and Ceanothtis. Although these plants are widely separated in any other classificatory scheme, they are all non-legumes producing root-nodules containing Bacillus radicicola . Each of these nodules has individual characteristics, but in every case the bacteria penetrate the root-hair and enter the cortex of the root without causing any morphological change, until a young lateral root during its passage through the cortex of the parent root becomes infected, when its development is so altered that it becomes a nodule. The plerome was already differentiated when the bacteria entered, therefore they attacked the cortical cells only, the stele retaining its central position and the growing point remaining apical (see Text-fig. i). The nodules which are characteristic of the Leguminosae are produced by infection of the root-hairs and cortex by the same organism, which here stimulates the cortical cells to increase in size, thus producing a local swelling which very soon becomes visible (see Pl. XIII, Fig. 6). A basal meristem