The Americana; a universal reference library, comprising the arts and sciences, literature, history, biography, geography, commerce, etc., of the world . FlG. 13.— Mature fruitof powdery mildew,with escaping magnified. Fig. 12 Fig. — Sexual organs of Erysiphe and formation offruit. Highly magnified. moved from their aquatic ancestors. The plantbody consists of branch-ing filaments which creepover the surfaces of theirhosts, from which theyobtain food by means ofroot-like absorbing or-gans, which penetratethe host cells. Certainbranches forin spores bythe simple process ofs
The Americana; a universal reference library, comprising the arts and sciences, literature, history, biography, geography, commerce, etc., of the world . FlG. 13.— Mature fruitof powdery mildew,with escaping magnified. Fig. 12 Fig. — Sexual organs of Erysiphe and formation offruit. Highly magnified. moved from their aquatic ancestors. The plantbody consists of branch-ing filaments which creepover the surfaces of theirhosts, from which theyobtain food by means ofroot-like absorbing or-gans, which penetratethe host cells. Certainbranches forin spores bythe simple process ofseparating their terminalcells in succession andthis is done so abun-dantly that the sporesform powdery masses onthe surface of the spores float awayon wind currents, andthose that >;erminate onsimilar hosts give rise tonew plants. The sexual organs (egg-cells and antherids)occur on the creeping filaments, and are short lat-eral branches, the former somewhat thicker thanthe slender antherids. (Fig. 12.) The two comein contact with one another, and the protoplasmiccontents of the antherid pass into the egg-cellfertilizing it. As a
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectencyclo, bookyear1908
