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“gymnosperms”: non-flowering seed plants PowerPoint Presentation
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“gymnosperms”: non-flowering seed plants

“gymnosperms”: non-flowering seed plants

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“gymnosperms”: non-flowering seed plants

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  1. “gymnosperms”: non-flowering seed plants • Alpha FamiliesBeta Families • Cycadales (Order) Welwitschiaceae • Ginkgoaceae Podocarpaceae • Pinaceae Araucariaceae • Cupressaceae • (including Taxodiaceae) • Taxaceae • Ephedraceae • Gnetaceae

  2. “gymnosperms” Cycadales -- (Cycadaceae, Zamiaceae, Stangeriaceae) the cycad families (11/185; tropical and subtropical) • Plants seed plants, dioecious • Habit shrubs or trees with leaves arranged in terminal rosettes • Leaves tightly alternate forming a dense terminal rosette; pinnately compound; some with circinate vernation • Pollen borne on strobili with many spirally arranged scales; 6-manypollen sacs per scale (microsporophylls), on underside (abaxial) • Ovules borne on strobili with many spirally arranged peltate scales or megasporophylls; Cycadaceae: 2-8 ovules on margin of megasporophyll Zamiaceae: 2 ovules underneath peltate-shaped megasporophyll • Seedslarge, fleshy coat

  3. “gymnosperms” Ginkgoaceae --the maidenhair tree family(1/1; found in Se Asia) • Plants seed plants, dioecious • Habit trees • Leaves alternate;simple, fan-shaped with dichotomous venation; borne on long and short shoots; petiolate • Pollen borne on spike-like clusters of sporangiophores; arising from axil of bud scale or leaf on short shoot; 2 reflexed pollen sacs/sporangiophore • Ovules borne on forking “peduncle” arising from axil of leaf on short shoot; 2 (3+) erect ovules each with subtending collar • Seeds large, fleshy coat

  4. “gymnosperms” Pinaceae -- the pine family(9-12/210; cosmopolitan) • Plants seed plants, monoecious • Habit shrubs or trees • Leaves alternate or closely fascicled on determinate or indeterminate short shoots; simple and linear to needle-like • Pollen borne on strobili with many spirally arranged scales; 2 pollen sacs per scale, on underside of scale (abaxial) • Ovules borne on cones (scale/bract complex) woody at maturity with many spirally arranged scales, flattened and ± free from subtending bracts; 2 ovules per cone scale, on top of scale (adaxial) • Seeds usually winged (rarely wingless)

  5. “gymnosperms” Cupressaceae --the cypress family(includes Taxodiaceae) (28/156; cosmopolitan) • Plants seed plants, monoecious or dioecious • Habit shrubs or trees • Leaves alternate, opposite, or whorled;simple and scale-like, awl-shaped or linear • Pollen borne on strobili with many scales; 2-9 pollen sacs per scale, on underside of scale (abaxial) • Ovules borne on cones (scale/bract complex) usually woody at maturity (fleshy in Juniperus) with several to many scales, flattened or often peltate; wholly adnate to subtending bract; 2-many ovules per cone scale, on top of scale (adaxial) • Seeds small, wingless or narrowly winged

  6. “gymnosperms” Taxaceae --the yew family(5/17-20; widely distributed, mostly northern hemisphere) • Plants seed plants, dioecious (rarely monoecious) • Habit shrubs or trees • Leaves alternate;simple and linear or needle-like, decurrent on twigs • Pollen borne on strobili (look like cones) with several flattened sterile basal scales and 4-32 spirally arranged or whorled, peltate or ± flattened structures called sporangiophores that each bear 2-9 pollen sacs • Ovules solitary or in pairs, borne on reduced cones (one scale) terminal on short shoots • Seeds solitary, surrounded by a tubular green or red fleshy aril

  7. “gymnosperms” Taxaceae --comments • Comments: interesting coniferous family: you commonly see Taxus cultivated around Cornell campus. Which is more commonly planted, female plants or male plants? Taxus brevifolia (from the Pacific Northwest) is the source of Taxol, a treatment for breast cancer. • The aril is bright red in Taxus and green in Torreya, which is named after the famous American botanist John Torrey (1796-1873).

  8. “gymnosperms” Ephedraceae --the mormon-tea family(1/40; desert and semidesert regions of Northern Hemisphere and South America) • Plants seed plants, dioecious • Habit shrubs, woody vines (rarely trees) with jointed green, photosynthetic stems • Leaves opposite or whorled, simple, scale-like, often deciduous • Pollen borne on spike-like strobili with 1-8 polleniferous structures on a “filament” (each with 1-several pollen sacs) each subtended by a pair of bracts • Ovules borne on strobili with 1-3 ovulate structures each subtended by 2-4 pairs or whorls of scale-like bracts • Seeds dry or seeds and subtending structures fleshy Comments: long-used in Chinese medicine, also as a tea by western settlers. Synthetic analog (pseudoephedrine) of active compound in many cold remedies.

  9. “gymnosperms” Gnetaceae --the gnetum family(1/30; Pantropical) • Plants seed plants, dioecious (monoecious) • Habit shrubs, woody vines or trees • Leaves opposite, simple, entire, pinnately veined, petiolate • Pollen borne on aggregations of polleniferous structures with 1 or 2 pollen sacs (on “filaments?”) each structure surrounded by a tubular bract • Ovules borne whorled on spike-like clusters with a solitary ovule surrounded by a tubular bract • Seeds large, with tubular bracts forming a fleshy outer layer Comments: leaves, seeds, and tubers of several species eaten in Southeast Asia and Africa

  10. b family “gymnosperms” Welwitschiaceae --the welwitschia family(1/1; coastal desert of southwest Africa) • Plants seed plants, dioecious • Habit woody/fleshy obconical stem with long tap root • Leaves 2 opposite, strap-shaped, persisting throughout the life of the plant and growing from the base • Pollen stalked polleniferous structures with 3 pollen sacs born in strobili with a non- functional ovule in the center; strobili borne on branched axes • Ovules also in strobili on branched axes, ovule borne in bract axile enclosed by two pairs of bracts, the inner pair fused around the ovule • Seeds with conspicuous wings formed by inner pair of bracts Comments: a truly bizarre plant, very slow growing and long-lived (more than 1000 years); vessels present

  11. b family “gymnosperms” Araucariaceae --the araucaria family(3/40; Asian tropics and south temperate South American and Australian region) • Plants seed plants, dioecious (rarely monoecious) • Habit trees • Leaves alternate or opposite, simple and needle-like, awl-shaped or ovate • Pollen borne on strobili with many scales; many pollen sacs per scale, on underside of scale (abaxial) • Ovules borne on cones (scale/bract complex) woody with many spirally arranged, flattened scales, wholly or partially adnate to subtending bract; ovules usually 1 (rarely 2) per cone scale, on top of scale (adaxial) or embedded in scale; cones disarticulating at maturity • Seeds winged and breaking free from cone or wingless and disspersed as a unit with scale/bract complex

  12. b family “gymnosperms” Podocarpaceae --the podocarp family(13-17/172; south temperate and tropical) • Plants seed plants, dioecious or monoecious • Habit trees or shrubs, rarely root parasites, branches sometimes flattened and leaf-like (cladodes) • Leaves alternate ( rarely opposite), simple and needle-like, scale like or with flattened blades • Pollen borne on strobili with many spirally-arranged scales; 2 pollen sacs per scale, on underside of scale (abaxial) • Ovules borne on spikelike or reduced cones with 1-2 terminal ovules, each adnate to a cone scale and bract and to a swollen fleshy cone axis • Seeds dry or fleshy sometimes with fleshy aril