psilophyten.

Brit.

/ˈsʌɪləfʌɪt/, U.S.

/ˈsaɪləˌfaɪt/

Origin: Formed within English, by compounding. Etymons: psilo- comb. form, -phyte comb. form.

Etymology: < psilo- comb. form + -phyte comb. form. In sense 2 after scientific Latin Psilophyta, division name (W. Zimmermann 1926, in Zeitschr. f. Bot. 19 129; < Psilophyton, genus name (J. W. Dawson 1859, in Q. Jrnl. Geol. Soc. 15 487)); compare German Psilophyten, plural noun (1925 or earlier).

1. Ecology. A plant that is adapted for a dry savannah environment; the growth form characteristic of such a plant.

ΚΠ

1909 E. Warming et al. Oecol. Plants iii. xxxiv. 136 The following oecological classes may be distinguished:—... D. The climate is very dry... Class 10. Psilophytes (of formations on savannah).

1927 New Phytologist 26 291 The Chersophytes..have already been sufficiently dealt with, as have also the Mesophytes, sclerophyllous plants and Psilophytes (grassland plants).

1956 Amer. Midland Naturalist 56 457 The remaining portion of the hill is..covered by a mantle of soil thick enough to support a more or less complete plant cover in which psilophytes predominate.

1976 Jrnl. Ecol. 64 172 (figure) Life form... Psilophyte.

2. Botany and Palaeontology. Any of various extinct primitive vascular plants of the Upper Silurian and Devonian periods, lacking true roots and leaves but having a creeping rhizome and a cylindrical branching stem with a central vascular strand, sometimes bearing scales or leaf-like branchlets. Also: a member of the extant order Psilotales, comprising two genera ( Psilotum and Tmesipteris) of small tropical and subtropical plants that superficially resemble these fossils.The extant Psilotales were formerly classified in a division Psilophyta together with the fossil forms, but they are now thought to be more closely allied to ferns, and are often placed in a division called Psilotophyta. The fossil forms are now generally thought to represent a range of early vascular plant types, and probably not a unified group, some perhaps being related to the clubmosses.

ΚΠ

1933 Bull. Torrey Bot. Club 60 75 A..Lepidophyte almost as old as the middle Devonian Psilophytes (Psilophyton, Rhynia, Hornea, Asteroxylon) which have made such a stir in paleobotanical circles.

1959 Evolution 13 264/1 The problems of evolution posed by this earliest land vegetation—the Psilophyte Paleoflora—have been especially difficult to resolve.

1962 D. J. Merrell Evol. & Genetics xiv. 152 Certain psilophytes have very small leaves suggesting the club mosses, while others indicate leaf formation of a different type.

1998 L. Margulis & K. V. Schwartz Five Kingdoms (ed. 3) 393/2 Rhynia sporangia were borne singly at the tips of the stems rather than in the axils of outgrowths as in present-day psilophytes.

This is a new entry (OED Third Edition, September 2007; most recently modified version published online March 2022).

单词	psilophyte
释义	psilophyten. Brit. /ˈsʌɪləfʌɪt/, U.S. /ˈsaɪləˌfaɪt/ Origin: Formed within English, by compounding. Etymons: psilo- comb. form, -phyte comb. form. Etymology: < psilo- comb. form + -phyte comb. form. In sense 2 after scientific Latin Psilophyta, division name (W. Zimmermann 1926, in Zeitschr. f. Bot. 19 129; < Psilophyton, genus name (J. W. Dawson 1859, in Q. Jrnl. Geol. Soc. 15 487)); compare German Psilophyten, plural noun (1925 or earlier). 1. Ecology. A plant that is adapted for a dry savannah environment; the growth form characteristic of such a plant. ΚΠ 1909 E. Warming et al. Oecol. Plants iii. xxxiv. 136 The following oecological classes may be distinguished:—... D. The climate is very dry... Class 10. Psilophytes (of formations on savannah). 1927 New Phytologist 26 291 The Chersophytes..have already been sufficiently dealt with, as have also the Mesophytes, sclerophyllous plants and Psilophytes (grassland plants). 1956 Amer. Midland Naturalist 56 457 The remaining portion of the hill is..covered by a mantle of soil thick enough to support a more or less complete plant cover in which psilophytes predominate. 1976 Jrnl. Ecol. 64 172 (figure) Life form... Psilophyte. 2. Botany and Palaeontology. Any of various extinct primitive vascular plants of the Upper Silurian and Devonian periods, lacking true roots and leaves but having a creeping rhizome and a cylindrical branching stem with a central vascular strand, sometimes bearing scales or leaf-like branchlets. Also: a member of the extant order Psilotales, comprising two genera ( Psilotum and Tmesipteris) of small tropical and subtropical plants that superficially resemble these fossils.The extant Psilotales were formerly classified in a division Psilophyta together with the fossil forms, but they are now thought to be more closely allied to ferns, and are often placed in a division called Psilotophyta. The fossil forms are now generally thought to represent a range of early vascular plant types, and probably not a unified group, some perhaps being related to the clubmosses. ΚΠ 1933 Bull. Torrey Bot. Club 60 75 A..Lepidophyte almost as old as the middle Devonian Psilophytes (Psilophyton, Rhynia, Hornea, Asteroxylon) which have made such a stir in paleobotanical circles. 1959 Evolution 13 264/1 The problems of evolution posed by this earliest land vegetation—the Psilophyte Paleoflora—have been especially difficult to resolve. 1962 D. J. Merrell Evol. & Genetics xiv. 152 Certain psilophytes have very small leaves suggesting the club mosses, while others indicate leaf formation of a different type. 1998 L. Margulis & K. V. Schwartz Five Kingdoms (ed. 3) 393/2 Rhynia sporangia were borne singly at the tips of the stems rather than in the axils of outgrowths as in present-day psilophytes. This is a new entry (OED Third Edition, September 2007; most recently modified version published online March 2022). < n.1909
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