Bot. [f. THALL-US + -GEN, after exogen, endogen, etc.] = THALLOPHYTE.
1846. Lindley, Veg. Kingd., 2. Those simpler plants which exist without the distinction of leaf and stem, are also destitute of flowers…. Among the many names that Botanists have given such plants, that of Thallogens is here preferred.
1857. Berkeley, Cryptog. Bot., § 55. 69. Thallogens (plants in which there is a fusion of root, stems, and leaves into one general mass).
1858. Carpenter, Veg. Phys., § 123.
Hence Thallogenic, Thallogenous adjs., of or pertaining to the thallogens; of the nature of a thallogen.
1854. Balfour, in Encycl. Brit. (ed. 8), V. 146/1. Lichens … belong to the Thallogenous division of Cryptogamics.
1857. H. Miller, Test. Rocks, i. 9. The first class … in the ascending order is this humble thallogenic class.
