2 Pinophyta / Coniferophyta Pinophyta FamiliesPinaceae – pines & spruces etc.Cupressaceae – Cypress / Redwood familyPodocarpaceae – Podocarp familyAraucariaceae – Norfolk Isl. Pine familyTaxaceae – Yew familyCephalotaxaceaeSciadopityaceae – Umbrella-pine family
3 Phylogeny of the Pinophyta based on cladistic analysis of molecular data. (Derived from papers by A. Farjon and C. J. Quinn & R. A. Price in the Proceedings of the Fourth International Conifer Conference, Acta Horticulturae 615 (2003))
4 Family: CupressaceaeIt is the most widely distributed of all gymnosperm families, occurring in diverse habitats on all continents except AntarcticaWetlands dry soils; sea level high mountain elevationsConsists of 32 genera and 148 species¾ of species occur in N. Hemisphere
5 CupressaceaeThis family was formerly divided (on the basis of leaf morphology) into:Cupressaceae (sensu stricto)Leaves opposite & scale-like or whorled and linearTaxodiaceaeleaves mostly alternateRecent study of plastid (rbcL – ribulose biphosphate carboxylase) molecular sequences has further confirmed the close relationship between the Cupressaceae “sensu stricto” and the genera formerly assigned to the Taxodiaceae
6 Cupressaceae Similarities between Cupressaceae & Taxodiaceae include: Fusion of cone scale & bractLateral wings on seeds (derived from the seed coat)≥ 2 microsporangia per microsporophyll≥ 2 seeds per cone scaleShedding of dwarf shootsNon-saccate pollen with no prothallial cell developmentClustered archegoniaPeltate cone scalesDNA sequences
7 Cupressaceae Trees or shrubs Resinous & pycnoxylic: fragrant, insecticidal, fungicidal woodBark fibrous and furrowed (smooth or exfoliating in plates in some Cupressus and Juniperus species)Twigs terete, angled, or flattened. Dorsiventrally clothed by scale-like leaves or by decurrent leaf basesBuds undifferentiated and inconspicuous (except in Sequoia, Juniperus)Leaves simple; spirally arranged, or basally twisted to appear 2-ranked
8 leaves with twisted basal portion so they appear 2-ranked
9 CupressaceaeRoots fibrous to woody (bearing aboveground “cypress knees" in Taxodium).Leavessimple, usually persisting 3-5 (≤12) yearsScale-like leaves deltate; otherwise linear, decurrent, sessile or petiolatemature leaves appressed or spreading, often differing between lateral and leading shoots (twigs heterophyllous), sometimes strongly dimorphic on each twigalternate and spirally arranged but sometimes twisted so as to appear 2-ranked, or opposite in 4 ranksshed with lateral shootsMonoecious (but dioecious in Juniperus)
12 Cupressaceae Male/pollen cones mature and shed annually, Solitary & terminal (rarely in clusters)simple, spherical to oblongsporophylls overlap, bearing 2-10 abaxial microsporangia (pollen sacs)pollen spheric & non-saccateNo prothallial cells during development
13 Cupressaceae In the female cones maturing in 1-2 seasons shed with short shoots or persisting indefinitely on long-lived axes (shattering at maturity in Taxodium)compound, solitary, terminal (rarely in clusters )scales overlapping or abutting, fused to subtending bracts with only bract apex sometimes free
14 Cupressaceae Female cones: Seeds 1 – 20 per scale The ovuliferous scale and associated bract are fused for most of their common length.Each scale-bract complex are peltate or basally attached; flattened and woody (juicy in Juniperus) at maturityOvules are erect (micropyle faces away from cone axis) and they vary in number from 1 – 20 adaxially; however, may invert during maturity (e.g. Sequoia and Sequoiadendron)Archegonia clustered and variable in number/ovuleSeeds 1 – 20 per scaleMay or may not have 2-3 symmetric or asymmetric wingsEmbryo with 2-15 cotyledonsDuring embryogenesis the zygote shows some variations.
15 Cupressaceae The zygote divides into eight free nuclei Two tiers are formed:a lower tier of 4 embryonal cells andan upper tier of 4 cells that open towards the archegonial neckThe cells of the upper tier divide again into a middle / pro- suspensor tier and an upper tier giving three tiers (fig C).
16 Cupressaceae The number of cells may vary in each tier. The prosuspensor cells elongate and push the embryonal cells out of the archegonium.Later the primary embryonal cells divide transversely to cut off:an upper tier of suspensor cells anda lower tier of embryonal cells.Later the suspensor cells start elongating (after the prosuspensor cells stop elongation) and cleavage takes place.So cleavage polyembryony takes place.
17 Pinophyta / Coniferophyta Pinophyta FamiliesPinaceae – pines & spruces etc.Cupressaceae – Cypress / Redwood familyPodocarpaceae – Podocarp familyAraucariaceae – Norfolk Isl. Pine familyTaxaceae – Yew familyCephalotaxaceaeSciadopityaceae – Umbrella-pine family
18 Podocarpaceae Second-largest conifer family, of the Pinophyta Mainly Southern Hemisphere conifersConsist of genera and about species of evergreen trees and shrubs.Trunk usually straight and with more or less horizontal branchesLeaves arelanceolate to oblong, falcate (sickle-shaped) in some species,a distinct midribspirally phyllotaxy
19 Podocarpus aristulatus - branch with ovulate cones
21 Podocarpaceae - reproduction Dioecious (rarely monoecious)Pollen cones usually catkin-likestamens numerous, close together,2 sporangia / microsporophyllpollen grains with 2 (0-3) saccaeThe male/pollen cones are 5-20 mm long, often clustered several together
22 Podocarpaceae - reproduction Female cones maturing in one year, much reduced to a few fleshy bracts or scalespendant, usually borne on a thin peduncle, containing a single inverted ovuleIn the female cone the ovuliferous scale is folded around the ovule to form an extra envelope called the epimatium which is either partially or completely fused with the integument.
23 Podocarpaceae - embryogeny During embryogenesis 4 – 5 free nuclear divisions occur and gives 16 – 32 nuclei and then cell walls develop and results in the formation of two tiers.These organize themselves into upper (15-22 celled) and embryonal (9-12 celled) tiers. No rosette tier is present.
24 Podocarpaceae - reproduction Cells of upper tier divide open upper tier and suspensor tiersEmbryonic cells undergo nuclear division binucleate cellsSuspensor tier pushes embryonal tier into gametophyteLater bi-nucleate embryonal cells divide tetrads of cellsCleavage polyembryony is rare; mostly simple polyembryonyThe embryo has 2 cotyledons
27 Pinophyta / Coniferophyta Pinophyta FamiliesPinaceae – pines & spruces etc.Cupressaceae – Cypress / Redwood familyPodocarpaceae – Podocarp familyAraucariaceae – Norfolk Isl. Pine familyTaxaceae – Yew familyCephalotaxaceaeSciadopityaceae – Umbrella-pine family
28 Family: Araucariaceae Three genera with 40 speciesMostly restricted to S. HemisphereEvergreen trees, typically with a single stout trunk and very regular whorls of branches, giving them a formal appearanceSeveral have edible seeds similar to Pinus sp., and others produce valuable resin and amberDioecious or monoeciousMale cones relatively large, cylindricalnumerous microsporophylls±12 inverted pollen sacspollen grains non-saccate and exine pitteda number of prothallial cells are produced.
30 Araucariaceae The female cones are almost spherical, subglobose to ovoidusually borne erectmaturing in two yearsrelatively large and milkyfalling upon maturity or disintegrating on treescales one-seeded, without distinct bracts. The ovuliferous scale is intimately fused with the bract scale except in Araucaria.Cotyledons 4, often fused into 2 double cotyledonsThe embryogenesis in Araucariaceae differs from the other conifers.Free nuclei divisions of the zygote takes place until there are about 32 nuclei in Araucaria and 64 nuclei in Agathis.
31 AraucariaceaeInitially all the nuclei are grouped in the center of the egg cell.Cell walls are then laid down and the cells are arranged in a central group with 2 tiers of cells surrounded by an outer jacket on all sides.The upper cells of the jacket (those facing the archegonial neck) elongate to form the suspensor, whereas the cells towards the chalazal end act as cap cells (see fig).
32 AraucariaceaeThe upper tier of the central two tiers divides periclinally to form an upper tier of secondary suspensor cells and the lower tier of embryonal cells.The latter divide and develop into the embryo proper that has two cotyledons.There is no cleavage polyembryony.
33 Pinophyta / Coniferophyta Pinophyta FamiliesPinaceae – pines & spruces etc.Cupressaceae – Cypress / Redwood familyPodocarpaceae – Podocarp familyAraucariaceae – Norfolk Isl. Pine familyTaxaceae – Yew familyCephalotaxaceaeSciadopityaceae – Umbrella-pine family
34 Taxaceae 5 Genera, 17 species Small to moderately sized highly branched evergreen trees or shrubsUsually neither resinous nor aromaticno (or very few) resinous canalsLinear, flattened leaves with acute apexThe wood is pycnoxylicDioecious (rarely monoecious)The male cones are 2-5 mm longThe female cones are highly reduced, with just one ovuliferous scale and one seed
35 TaxaceaeThe Taxaceae and Cephalotaxaceae may be associated with the Podocarpaceae because of the solitary ovules associated with fleshy coveringsTaxus is the type genus of this familyPlants are mostly unisexual and rarely monecious.Taxus is represented by 9 species. They are found in North America, Malaysia and Europe.The wood of Taxus is very elastic and is used in making bows in archery.Taxus brevifolia and T. canadensis are the sources of paclitaxel (taxol®) , a chemo-therapeutic drug used in breast and lung cancer
36 Taxaceae - reproduction The microsporangia are arranged in small male / pollen cones.Pollen cones solitary or clusteredAxillaryglobose to ovoidsporophylls bearing microsporangia (pollen sacs)pollen ± spherical no saccae
38 Taxaceae - reproduction Prothallial cells are not formed, the androspore cell acts directly as an antheridal initialThe microspore nucleus divides periclinally to produce:The antheridal initial which divides to form a tube cell and a generative cell.The generative cell may divide periclinally to form a spermatogenous cellThe spermatagenous cell divides ultimately into two male gametes / male cells.
39 Taxaceae - reproduction The ovule has an aril which incompletely surrounds itThe mature aril is brightly red coloured, soft, juicy and sweet, and is eaten by birds which then disperse the hard seed undamaged in their droppings.Taxaceae members are unique as their solitary seeds are not associated with cone scalesWhy a conifer?embryology – chemistrywood anatomy – leaf & pollen morphologyCone thought to be lost
40 Taxaceae - reproduction After fertilization up to 32 free nuclei are formed by the zygote.Then they organize themselves into 9 – 13 open upper cells and 9 – 13 suspensor cells and 6 – 14 embryonal cells (no rosette cells are present).Polyembryony rarely occurs in this groupSeeds 1 per "cone," erect, not winged, hard seed coat
42 Young cones developing Torreya californicaYoung cones developing
43 Pinophyta / Coniferophyta Pinophyta FamiliesPinaceae – pines & spruces etc.Cupressaceae – Cypress / Redwood familyPodocarpaceae – Podocarp familyAraucariaceae – Norfolk Isl. Pine familyTaxaceae – Yew familyCephalotaxaceaeSciadopityaceae – Umbrella-pine family
44 Cephalotaxaceae a small group of conifers 3 genera containing ~ 20 speciesclosely allied to the Taxaceaeincluded in that family by some botanistshighly branched small trees/shrubsFamily Taxaceae Cephalotaxaceae Cone aril partly encloses seed fully encloses seed Cone maturation 6-8 months 18-20 months Mature seed length 5-8 mm 12-40 mm
45 Phylogeny of the Taxaceae and Cephalotaxaceae - note that both groups have evolved from within the other conifers
46 Cephalotaxaceae Shrubs or small trees Leaves simple and usually spirally arrangedPlants are dioeciousMale cones arise in clusters of 6-8 cones in axils of short-shoot scale leaves3-4 microsporangia borne abaxiallyPollen grain spherical; bear no saccaeNo prothallial cells formed during pollen grain development
48 Globose pollen cones of Cephalotaxus harringtonia
49 CephalotaxaceaeMegasporangiate cones occur singly in the axils of lowermost leaves of young branchesAppear green when young but redden at maturity“Cones” consist of a central axis bearing 5-7 pairs of bractsEach bract bears 2 ovules within its axil separated by reduced cone scaleUsually one or two ovules ripen in one cone
50 Cephalotaxaceae - reproduction Zygote divides into 16 free nuclei which evenly associates upper and embryonal tiersUpper tier divides into open tier and prosuspensor tierThe open tier cells disorganise eventually and prosuspensor cells elongate and push the embryonal tier out of the archegonium at the expense of female gametophyteProsuspensors degenerate after secondary suspensor formation and embryonal cells divide large embryonal tissueNo cleavage polyembryony
52 Pinophyta / Coniferophyta Pinophyta FamiliesPinaceae – pines & spruces etc.Cupressaceae – Cypress / Redwood familyPodocarpaceae – Podocarp familyAraucariaceae – Norfolk Isl. Pine familyTaxaceae – Yew familyCephalotaxaceaeSciadopityaceae – Umbrella-pine family
53 SciadopityaceaeThe family was formerly included as a genus within Cupressaceae (Taxodiaceae), but recent genetic studies (Brunsfeld et al. 1994) have shown that it is clearly not allied with that group.