a. [f. mod.L. exōgen-a, -us (see EXOGEN) + -OUS.] a. Bot. Growing by additions on the outside; of the nature of an exogen; pertaining to or characteristic of the exogens. b. Path. = EXOGENETIC. c. Anat. Of a portion of bone (see quot. 1854); opposed to autogenous.
a. 1830. Lindley, Nat. Syst. Bot., Introd. 19. A section of the trunk of an Exogenous plant exhibits bark on the outside.
1833. Lyell, Princ. Geol., III. 98. There is a considerable analogy between the mode of increase of a volcanic cone and that of trees of exogenous growth.
1872. H. Macmillan, True Vine, iii. 76. As examples of exogenous plants may be mentioned the oak … the apple … and the rose.
fig. 1874. Mrs. Whitney, We Girls, ix. 191. I am going to try if one little bit of social life cannot be exogenous.
1885. Mrs. Lynn Linton, Stabbed in Dark, iv. 40. [He had] a more exogenous nature than had the other; a nature which lived more on, and adopted more from, externals.
b. 1883. Fortn. Rev., 1 Aug., 177. An exogenous contagion is one that depends for its potency upon favouring conditions outside the body.
c. 1854. Owen, in Circ. Sc. (c. 1865), II. 48/2. Parts that grow out from previously ossified parts are called ‘exogenous.’
Hence Exogenously adv.
1879. Spectator, 6 Sept., 1125/1. Why should it [the Temple] not grow exogenously, building not towards the inside, but the outside?
1890. Williamson, in Nature, 17 April, 573. The former of these plants possessed a highly organized, exogenously developed xylem zone.
