| 释义 |
‖ isidium Bot.|aɪˈsɪdɪəm|
Pl. isidia.
[ad. mod.L. generic name Isidium (E. Acharius Lichenographiae Suecicae Prodromus (1798) 87), formerly used to include all lichens bearing isidia, f. Isis, Isid-em, Isis (in reference to her disc and horns).]
One of a number of coral-like or wart-like elevations or excrescences of the thallus in certain lichens, having the function of soredia.
1866Treas. Bot. 629/2 Isidium, a coral-like elevation of the thallus of a lichen, bearing a globule at its end. 1882J. M. Crombie in Encycl. Brit. XIV. 557/2 Nylander observes..that the isidia in the Collemacei..‘show very clearly under the microscope the entire history of the evolution of the thallus’.
Hence iˈsidial a., of or pertaining to an isidium; iˈsidiate, isidiiferous |aɪˌsɪdɪˈɪfərəs|, isidiophorous |-ˈɒfərəs| adjs. [see -ferous, -phorous], bearing isidia; isidioid |aɪˈsɪdɪɔɪd|, isidiˈose adjs., resembling or of the nature of an isidium; characterized by or provided with isidia.
1856W. L. Lindsay Brit. Lichens 43 The isidioid thallus resembles the tartareous in being usually pale or whitish. 1857Berkeley Cryptog. Botany 418 Many other forms are assumed by the crusts of Lichens;..the isidioid, in which the thallus is broken up into short erect cylindrical projections. 1882J. M. Crombie in Encycl. Brit. XIV. 554/1 This isidioid condition in crustaceous thalli is the basis of the old pseudo-genus Isidium. Ibid. 556/1 On the margin of the thallus of isidiiferous states of Peltigera canina. 1887Syd. Soc. Lex., Isidioid,..applied to those lichens which are covered with a dense mass of conical soredia. 1921A. L. Smith Lichens iii. 149 In the genus [sc. Isidium] were included the more densely isidioid states of various crustaceous species. Ibid. 150 The centre of the isidial tuft [of Umbilicaria pustulata] may fall out. 1959U. K. Duncan Guide to Study of Lichens 7 P[armelia] crinita... Resembles an isidiate form of P. trichotera. 1962Lichenologist II. 3 P[armelia] reddenda is a pseudo⁓cyphellate species with peculiar granular or granular-isidiate outgrowths on the upper surface. 1967M. E. Hale Biol. Lichens i. 22 It is not apparent that isidiate species hold any advantage over non-isidiate species. 1970Lichenologist IV. 216 Further development of the isidial initials leads to a definite dorsi-ventral organization. |