PHYLOGENETIC DIVERSIFICATION OF EARLY CRETACEOUS SEED PLANTS: THE COMPOUND SEED CONE OF DOYLEA TETRAHEDRASPERMA [X23745] (matrix)

Abstract Angiosperms that are biotically pollinated typically produce flowers with bright and contrasting colours that help to attract pollinators and hence contribute to the reproductive success of the species. This colourful array contrasts with the much less multicoloured reproductive structures of the four living gymnosperm lineages, which are mostly wind pollinated, though cycads and Gnetales are predominantly pollinated by insects that feed on surface fluids from the pollination drops. This review examines the possible evolutionary pathways and cryptic clues for flower colour in both living and fossil seed plants. It investigates how the ancestral flowering plants could have overcome the inevitable trade-off that exists between attracting pollinators and minimizing herbivory, and explores the possible evolutionary and biological inferences from the colours that occur in some living gymnosperms. The red colours present in the seed-cone bracts of some living conifers result from accumulation of anthocyanin pigments; their likely primary function is to help protect the growing plant tissues under particular environmental conditions. Thus, the visual cue provided by colour in flower petals could have first evolved as a secondary effect, probably post-dating the evolution of bee colour vision but occurring before the subsequent functional accumulation of a range of different flower pigments.

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Anatomically Preserved Early Cretaceous Bennettitalean Leaves: Nilssoniopteris corrugata n. sp. from Vancouver Island, Canada

Journal of Paleontology ◽

10.1017/s002233600005767x ◽

2014 ◽

Vol 88 (5) ◽

pp. 1085-1093 ◽

Cited By ~ 5

Author(s):

M. Madeleine Ray ◽

Gar W. Rothwell ◽

Ruth A. Stockey

Keyword(s):

Early Cretaceous ◽

Vascular System ◽

Vancouver Island ◽

Bundle Sheath ◽

Seed Plants ◽

Seed Plant ◽

Internal Anatomy ◽

Adaxial Surface ◽

Plant Fossils ◽

Entire Margin

Early Cretaceous fossilized leaves assignable to the extinct seed plant order Bennettitales occur within an exceptionally diverse Early Cretaceous (Valanginian) flora of anatomically preserved plant fossils at Apple Bay on Vancouver Island, British Columbia, Canada. One of the bennettitalean leaf types has an entire margin, with laminae that are attached near the adaxial surface of the midvein. Leaves are 10–15 mm wide with an adaxial surface that shows distinct corrugations, and a midrib that is exposed adaxially. The vascular system of the midrib consists of a crescent-shaped ring of collateral bundles. Lateral veins diverge from midrib at ∼90°, are typically simple but occasionally branch at base of the lamina. Vein density is 12–15 per cm. Leaves are hypostomatic with syndetocheilic stomata that are randomly oriented between veins. Internal anatomy consists of an adaxial hypodermis of closely-spaced isodiametric cells, mesophyll that is differentiated into adaxial palisade and abaxial spongy zones, and collateral bundles that show a distinct bundle sheath with bundle sheath extensions. This novel combination of characters represents the diverse bennettitalean genus Nilssoniopteris. Nilssoniopteris corrugata new species is only the second species of the genus for which internal anatomy is preserved. This species increases the known variation of bennettitalean leaf anatomy, and reinforces our appreciation for the global distribution of bennettitalean seed plants during the Mesozoic.

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New fossil Pinaceae from the Early Cretaceous of Mongolia

Botany ◽

10.1139/cjb-2016-0042 ◽

2016 ◽

Vol 94 (9) ◽

pp. 885-915 ◽

Cited By ~ 5

Author(s):

Fabiany Herrera ◽

Andrew B. Leslie ◽

Gongle Shi ◽

Patrick Knopf ◽

Niiden Ichinnorov ◽

...

Keyword(s):

Northern Hemisphere ◽

Early Cretaceous ◽

Distal Portion ◽

Adaxial Surface ◽

Anatomical Features ◽

Central Mongolia ◽

Seed Cone

Exceptionally well-preserved pinaceous leaves and seed cones are abundant in unconsolidated Early Cretaceous lignites in central Mongolia. These fossils include two seed cones, both of which have helically arranged bract–scale complexes with two winged seeds on the adaxial surface. The larger of the two seed cones, described as Picea farjonii sp. nov., is cylindrical to ellipsoidal, and was borne terminally on a stout shoot. The bract is small and tridentate. Leaf bases on the shoots are helically arranged, and attached leaves are linear and flattened. In all of the morphological and anatomical features that are preserved, P. farjonii is very similar to extant Picea. The smaller seed cone, described as Pityostrobus stockeyae sp. nov., shows features of several genera of extant Pinaceae. This cone is ellipsoidal and was borne terminally on a long, slender shoot. The bract is thin and triangular proximally, but the distal portion is thicker, needle-like, and deciduous. Picea farjonii and Pityostrobus stockeyae were abundant in conifer-dominated swamps in Mongolia during the Aptian–Albian and provide further support for the importance of plants related to extant Pinaceae in the vegetation of the Northern Hemisphere at this time.

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