BIOLOGY 3404F EVOLUTION OF PLANTS Fall 2008

1. BIOLOGY 3404FEVOLUTION OF PLANTSFall 2008 Lecture 15 Thursday Nov 13 2008 Chapter 18, Living Gymnosperms II: Coniferophyta

2. What are conifers? • Con – i – fer = cone-bearing • Most, but not all, produce seeds in cones composed of overlapping scales (modified leaves, or sporophylls), each with one or more often two seeds (matured, fertilized ovules) on the upper side. A few produce fleshy false fruits. • Most, but not all, have evergreen, needle-like or scale-like leaves. Some are deciduous and others have broad leaves. • Many have resinous wood; none have vessels.

5. REPRODUCTION: • As in other gymnosperms, pollen is drawn into the micropyle and pollen chamber by drying-down of a pollination drop, then the pollen germinates to form a pollen tube which grows to the egg cell of one of two or three archegonia, and a sperm nucleus (non-motile) emerges to fertilize the egg. • In Pinus, fusion of male and female gametes may be delayed for a year or more after pollination. • All archegonia are commonly fertilized, but usually only one embryo develops fully.

6. Reproduction II • A pine seed has "three generations": the seed coat (integument) is of the parent sporophyte generation (2n), and within this is the megagametophyte generation (female, n) tissue surrounding the embryo (offspring, 2n), which consists of a hypocotyl-root axis, with cotyledons and apical meristem at one end, and another apical meristem and a root cap at the other (bottom). • The "nuts" of several species of pines are gathered and sold commercially.

7. Bristle-cone pine, Pinus longaeva, needles in fascicles of five, and young (left) and mature (right) ovulate cones

8. Pinus radiata microsporangiate cones shedding pollen

17. Classification (revised on basis of recent molecular data) Phylum Coniferophyta (= Pinophyta) (5 classes, each with a single order) Class Pinopsida: Order Pinales, family Pinaceae Class Cordaitopsida†: Order Cordaitales Class Voltziopsida†: Order Voltziales Class Coniferopsida: Order Coniferales Taxaceae, Cupressaceae, Taxodiaceae, Araucariaceae, Podocarpaceae, Phyllocladaceae, Cephalotaxaceae [Class Gnetopsida: Order Gnetales]

19. Class PINOPSIDAOrder Pinales, Family Pinaceae • 10-12 genera, 250 species • Ectomycorrhizal • Monoecious trees and shrubs with persistent needles (i.e., evergreen, except Larix) on long shoots or short shoots, separate or fascicled, and woody ovulate cones with overlapping spirally-arranged scales, distinct bracts and scales, 2 ovules per scale, and 3 to 18 cotyledons (polycotyledonous). • The dominant conifers of the northern hemisphere, although also found in the southern hemisphere.

20. Selected genera of Pinaceae • Abies (50 species) True firs, including A. balsamea, Balsam Fir • Cedrus (4) True cedars, natives of Mediterranean Africa • Larix (10-12) Larches, including L. laricina, Tamarack • Picea (50) Spruces, including P. glauca, White Spruce; P. mariana, Black Spruce; P. abies, Norway Spruce.

21. Selected genera of Pinaceae II • Pinus (70-100) Pines, including P. strobus, White Pine; P. resinosa, Red Pine; P. sylvestris, Scots Pine. Bristlecone pines are the oldest living things - at 4,900 years old (see p. 597). • Pseudotsuga (7) Pseudotsuga menziesii is Douglas Fir of western N. America, widely planted in forestry plantations • Tsuga (15) Tsuga canadensis is the Eastern Hemlock

22. Pinus palustris of SE U.S., with needles in bundles (fascicles) of three

23. Left, Pinus edulis seedling with spirally-arranged single needles (in bundles of two at maturity); Right, Pinus radiata grown from rooted fascicles of needles - the shoot meristem can re-create an entire plant

24. Abies balsamea

25. Larix decidua

26. Class CONIFEROPSIDA,Order Coniferales,Family Cupressaceae • 18-19 genera, 130 species • Endomycorrhizal • Monoecious or dioecious trees or shrubs with persistent scale-like or awl-shaped leaves and woody ovulate cones (scales fleshy in Juniperus), the bracts and scales fused, arranged oppositely or in whorls, peltate or overlapping, ovules 2 to many per scale, and 2 cotyledons (rarely 5-6). • Cosmopolitan

27. Selected genera of Cupressaceae • Calocedrus (3) C. decurrens is the Californian Incense "Cedar" • Chamaecyparis (7) C. nootkatensis is a common ornamental, derived from Yellow "Cedar" of the PNW; C. thyoides is the rare and endangered Atlantic White "Cedar" • Cupressus (15-20) Cypresses (the slender, dark conifers in van Gogh paintings) • Juniperus (60) Junipers, including J. virginiana, Eastern Red "Cedar"; J. communis, shrubby Common Juniper; many ornamental shrubs. • Thuja (5) Arbor-vitae, T. occidentalis is the Eastern White "Cedar"

28. Cupressus goveniana

29. Juniperus communis

30. Chamaecyparis obtusa, photo Walter S. Judd, from Judd et al. 2002

31. Thuja occidentalis, photo Walter S. Judd, from Judd et al. 2002

32. Order Coniferales, Family Taxodiaceae • 10 genera, 16 species • Endomycorrhizal • Monoecious trees with persistent or deciduous, linear to ovate or awl-shaped leaves, globose woody ovulate cones with peltate scales, partially or completely fused with bracts, 2 to 9 ovules per scale and 2 to 9 cotyledons. • Found in south-eastern and southwestern North America, Tasmania and eastern Asia.

33. Selected genera of Taxodiaceae • Cryptomeria (1) Cryptomeria japonica Japanese "Cedar" is commonly cultivated as an ornamental • Metasequoia (1) M. glyptostroboides is the Dawn Redwood, described as a fossil before it was discovered still growing in China! • Sequoia (1) S. sempervirens is the Californian Redwood (think ewoks in Star Wars III), grows to about 110 m (367 ft), 2,000 years in age • Sequoiadendron (1) S. giganteum is the Giant Sequoia, or Bigtree, not as tall as the Redwoods (311 ft), but reach a diameter of 8+ m and 4,000 years. • Taxodium (3) T. distichum is the Bald Cypress of southern swamps.

34. Cryptomeria japonica, photo by Walter S. Judd, from Judd et al. 2002

35. Metasequoia glyptostroboides, the dawn redwood, in China

37. Fossil of Metasequoia

38. Sequoia sempervirens, photo by Walter S. Judd, from Judd et al. 2002

39. Redwoods in coastal California

40. Sequoiadendron giganteum, the giant sequoia

41. Taxodium distichum, the bald cypress

42. Order Coniferales, Family Araucariaceae • 3 genera, 40 species • Endomycorrhizal except Wollemia which may have both EM & ECM • Monoecious or dioecious trees with needle-like or broad leaves, globose ovulate cones with bract and scale fused and ovule 1 per scale, cotyledons 2 or rarely 4 • A Gondwana family found in Australasia and southern S. America

43. Genera of Araucariaceae • Araucaria (18) including Monkey Puzzle Tree and Norfolk Island "Pine" • Agathis (20) Kauri, and Dammar "Pine" • Wollemia (1) Wollemi "Pine", thought to be extinct for 150 million years before discovered living just outside of Sydney in 1994!

44. Araucaria heterophylla, Norfolk Island Pine

45. Agathis australis(photo Christopher Campbell, from Judd et al. 2002)

46. Wollemi Pine, Wollemia nobilis, in forest near Sydney

47. Ovulate cone and branch with leaves in four rows

48. Modern Wollemia and Jurassic Araucaceae fossils

49. Order Coniferales, Family Podocarpaceae • 17 genera, ca. 125 species of Gondwana distribution • Endomycorrhizal • Monoecious or dioecious trees or shrubs with leaves of all types: scale-like, needle-like, lanceolate or ovate, terminal, solitary ovules often becoming enclosed by a fleshy aril, or with basal aril. • Another Gondwana family, mostly in the southern hemisphere, one species in Costa Rica.

50. Selected genera of Podocarpaceae, plus families 5-6 • Podocarpus (100) Podocarps, including P. andinus, the Plum-fruited "Yew" • Parasitaxus (1) The only known parasitic gymnosperm  • Family Phyllocladaceae (e.g., Phyllocladus) Endomycorrhizal • Family Cephalotaxaceae (Cephalotaxus; Himalayas to Japan) Endomycorrhizal