The Families of Gymnosperms
The Families of Gymnosperms | |
Japanese Umbrella Pine.
Vegetative. Evergreen; trees. Resinous. The leafy branchlets not flattened. The vegetative shoots of limited growth including highly specialised short-shoots. Mature leaves dimorphic; scale-like (on the long-shoots), or 2-veined, evidently representing pairs of ‘needles’ united lengthwise (on the short-shoots). Mature foliage leaves in tight clusters on short-shoots, each cluster with a basal sheath of scales, or not clustered (depending on interpretation of the peculiar leaves); whorled. Longitudinal resin canals present in the leaves; in a peripheral ring (this incomplete abaxially).
Reproductive organization. The ovules borne in female cones. The female cones woody. The seed-cone scales spirally arranged; deciduous, the cones disintegrating at maturity; woody. The ovules borne proximal-adaxially on the seed-cone scales. The bract-scales more or less free of the seed-cone scales in mature cones. The seed-cone scales 5–9 ovuled. The ovules anatropous.
Male cones subspherical, in terminal, compact clusters, with spirally arranged sporophylls. Pollen-sacs 5–9 per microsporophyll (?). Pollen without air bladders. Pollination anemophilous, involving a “liquid drop” mechanism.
Seeds and seedlings. Seeds winged. Cotyledons 2.
Wood anatomy. Growth rings distinct. Heartwood present and distinctively coloured. Latewood not conspicuous. Wood with a distinct odour; with a distinct taste; not greasy; without dimpled grain. Tracheids with neither alternate nor opposite bordered pits; without callitroid pit-border thickenings. Margins of the tori not scalloped. Earlywood tracheids without spiral thickenings. Axial parenchyma absent. Ray tracheids absent or very infrequent. Earlywood ray cells with horizontal walls thinner than those of the adjacent vertical tracheids above and below the ray. Latewood ray cells with unpitted horizontal walls. Ray cells without indentures; without nodular thickenings on their end walls. Ray tissue without crystals. Earlywood cross-field pits 1(-3), large and simple (or nearly so). Normal vertical resin ducts absent.
Geography, cytology. Japan.
Basic chomosome number, n = 10.
Taxonomy. 1 species (S. verticillata); Sciadopitys. Order Coniferales.
Miscellaneous. • Sciadopitys verticillata (Dallimore and Jackson). • Sciadopitys verticillata (Chittenden). • Cone-scale interpretation: Sciadopitys verticillata (Florin). • Wood anatomy: Sciadopitys verticillata.
To view the illustrations with detailed captions, go to the interactive key. This also offers full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2008 onwards. The families of gymnosperms. Version: 10th April 2008. http://delta-intkey.com’.
