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Gymnosperms of Laos

The gymnosperms are a group of seed-producing plants (spermatophytes) that includes conifers (Pinophyta), cycads, Ginkgo, and gnetophytes. The term “gymnosperm” comes from the Greek composite word γυμνόσπερμος (γυμνός gymnos, “naked” and σπέρμα sperma, “seed”), meaning “naked seeds”. The name is based on the unenclosed condition of their seeds (called ovules in their unfertilized state). The non-encased condition of their seeds stands in contrast to the seeds and ovules of flowering plants (angiosperms), which are enclosed within an ovary. Gymnosperm seeds develop either on the surface of scales or leaves, which are often modified to form cones, or solitary as in Yew, Torreya, Ginkgo.

The gymnosperms and angiosperms together compose the spermatophytes or seed plants. The gymnosperms are divided into six phyla. Organisms that belong to the Cycadophyta, Ginkgophyta, Gnetophyta, and Pinophyta (also known as Coniferophyta) phyla are still in existence while those in the Pteridospermales and Cordaitales phyla are now extinct.

Gymnosperms_Laotica

By far the largest group of living gymnosperms are the conifers (pines, cypresses, and relatives), followed by cycads, gnetophytes (Gnetum, Ephedra and Welwitschia), and Ginkgo biloba (a single living species).

The present review includes keys for identification and summary data on the nomenclature, morphology, ecology and distribution for all 33 species of gymnosperms hitherto recorded in the flora of Laos. They belong to 8 families and 15 genera. Important additions to these data were obtained during fieldwork in 2009-2013, when 58 localities containing 25 species from 14 genera and 8 families were explored and initially studied. Two species, Cycas laotica and Pinus cernua, are described as new species for science. Seven species, Cycas dolichophylla, C. inermis, C. macrocarpa, C. micholitzii, C. nongnoochiae, C. petraea and Taxus wallichiana, are found in Laos and represent new records for the flora of the country. Maps of the distribution and illustrations for the newly discovered gymnosperm species are provided. All observations, records and discoveries are based on reliable scientific literature and collected voucher herbarium specimens housed in main regional herbaria.

Title: Gymnosperms of Laos
Authors: Averyanov, , Leonid V.;
Nguyen, Tien Hiep;
Sinh, Khang Nguyen
Pham, The Van
Lamxay, Vichith;
Keywords: Species Index
Cycas
Cycas micholitzii
Cycas nongnoochiae
Gymnospermae;
Taxus wallichiana
Issue Date: 2014
Publisher: Nordic Journal of Botany
Citation: Scopus
Abstract: The present review includes keys for identification and summary data on the nomenclature, morphology, ecology and distribution for all 33 species of gymnosperms hitherto recorded in the flora of Laos. They belong to 8 families and 15 genera. Important additions to these data were obtained during fieldwork in 2009-2013, when 58 localities containing 25 species from 14 genera and 8 families were explored and initially studied. Two species, Cycas laotica and Pinus cernua, are described as new species for science. Seven species, Cycas dolichophylla, C. inermis, C. macrocarpa, C. micholitzii, C. nongnoochiae, C. petraea and Taxus wallichiana, are found in Laos and represent new records for the flora of the country. Maps of the distribution and illustrations for the newly discovered gymnosperm species are provided. All observations, records and discoveries are based on reliable scientific literature and collected voucher herbarium specimens housed in main regional herbaria.
Description: Nordic Journal of Botany, Volume 32, Issue 6, 1 December 2014, Pages 765-805
Nordic Journal of Botany
URI: http://onlinelibrary.wiley.com/doi/10.1111/njb.00498/abstract;jsessionid=84ACBB3740A4E6556A07CDB87532DDBD.f04t02
http://repository.vnu.edu.vn/handle/VNU_123/34093
ISSN: 0107055X
Appears in Collections: Bài báo của ĐHQGHN trong Scopus

 

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