{ ‖ } n. [ NL. merithallus, fr. Gr. &unr_;, or &unr_;, a part + &unr_; a young shoot. ] (Bot.) Same as Internode. [ 1913 Webster ]

‖n.; pl. Prothallia [ NL. ] (Bot.) Same as Prothallus. [ 1913 Webster ]

‖n.; pl. Prothalli [ NL., fr. Gr. &unr_; before + &unr_; a young shoot. ] (Bot.) The minute primary growth from the spore of ferns and other Pteridophyta, which bears the true sexual organs; the oophoric generation of ferns, etc. [ 1913 Webster ]

n. (Chem.) A salt of a hypothetical thallic acid. [ 1913 Webster ]

n. (Chem.) A hydrocarbon obtained from coal-tar residues, and remarkable for its intense yellowish green fluorescence. [ 1913 Webster ]

a. (Chem.) Of or pertaining to thallium; derived from, or containing, thallium; specifically, designating those compounds in which the element has a higher valence as contrasted with the thallous compounds; as, thallic oxide. [ 1913 Webster ]

a. (Bot.) Consisting of a thallus. [ 1913 Webster ]

n. [ Gr. &unr_; a young shoot or branch. ] (Chem.) An artificial alkaloid of the quinoline series, obtained as a white crystalline substance, C10H13NO, whose salts are valuable as antipyretics; -- so called from the green color produced in its solution by certain oxidizing agents. [ 1913 Webster ]

a. (Chem.) See Thallous. [ 1913 Webster ]

n. [ NL., fr. Gr. &unr_; young or green shoot or branch, twig. So called from a characteristic bright green line in its spectrum. ] (Chem.) A rare metallic element of the aluminium group found in some minerals, as certain pyrites, and also in the lead-chamber deposit in the manufacture of sulphuric acid. It is isolated as a heavy, soft, bluish white metal, easily oxidized in moist air, but preserved by keeping under water. Symbol Tl. Atomic weight 203.7. [ 1913 Webster ]

n. [ Gr. &unr_; young shoot or branch, frond + -gen. ] (Bot.) One of a large class or division of the vegetable kingdom, which includes those flowerless plants, such as fungi, algae, and lichens, that consist of a thallus only, composed of cellular tissue, or of a congeries of cells, or even of separate cells, and never show a distinction into root, stem, and leaf. [ 1913 Webster ]

a. [ Thallus + -oid. ] (Bot.) Resembling, or consisting of, thallus. [ 1913 Webster ]

‖n. pl. [ NL. See Thallophyte. ] (Bot.) A phylum of plants of very diverse habit and structure, including the algae, fungi, and lichens. The simpler forms, as many blue-green algae, yeasts, etc., are unicellular and reproduce vegetatively or by means of asexual spores; in the higher forms the plant body is a thallus, which may be filamentous or may consist of plates of cells; it is commonly undifferentiated into stem, leaves, and roots, and shows no distinct tissue systems; the fronds of many algae, however, are modified to serve many of the functions of the above-named organs. Both asexual and sexual reproduction, often of a complex type, occur in these forms. The Thallophyta exist almost exclusively as gametophytes, the sporophyte being absent or rudimentary. By those who do not separate the Myxophyta from the Tallophyta as a distinct phylum the latter is treated as the lowermost group in the vegetable kingdom. [ Webster 1913 Suppl. ]

n. [ Gr. &unr_; young shoot + -phyte. ] 1. (Bot.) A plant belonging to the Thallophyta. -- Thal`lo*phyt"ic a. [Webster 1913 Suppl.]

2. (Bot.) Same as Thallogen. [1913 Webster]

a. (Chem.) Of or pertaining to thallium; derived from, or containing, thallium; specifically, designating those compounds in which the element has a lower valence as contrasted with the thallic compounds. [ Written also thallious. ] [ 1913 Webster ]

‖n.; pl. Thalli [ NL., fr. Gr. &unr_; young shoot or branch, frond. ] (Bot.) A solid mass of cellular tissue, consisting of one or more layers, usually in the form of a flat stratum or expansion, but sometimes erect or pendulous, and elongated and branching, and forming the substance of the thallogens. [ 1913 Webster ]