The Americana; a universal reference library, comprising the arts and sciences, literature, history, biography, geography, commerce, etc., of the world . ere on the body ofthe plant) slender branches grow up and in turntheir ends become cut off by cross partitions.(Fig. 5.) The first end segments (the roundedones) are oogones, or in plainer words they areegg-organs, and in them one or more eggs areproduced. The second segments (slender) aremale organs called antherids, and the protoplasmthey contain has the function of the sper-matozoids of many plants (and animals). Atthe proper time the anth
The Americana; a universal reference library, comprising the arts and sciences, literature, history, biography, geography, commerce, etc., of the world . ere on the body ofthe plant) slender branches grow up and in turntheir ends become cut off by cross partitions.(Fig. 5.) The first end segments (the roundedones) are oogones, or in plainer words they areegg-organs, and in them one or more eggs areproduced. The second segments (slender) aremale organs called antherids, and the protoplasmthey contain has the function of the sper-matozoids of many plants (and animals). Atthe proper time the antherids puncture the egg-organs, and by the inflow of the contents of theformer the eggs are fertilized. Later theseeggs may germinate and produce new plants likethose on which they were borne. Dozmiy Mildews (Peronosfioracece) are mtichlike the water moulds, but instead of beingaqtiatic, they live in the tissues of land the water moulds they are composed ofbranching, non-septate filaments. The mainbody of the plant grows in the intercellttlarspaces of the host, where there is nearly as muchmoisture as under aquatic conditions. (Fig. 6.). Fig. 6.— Portion of a filament of Albugo Candida, withits haustoria penetrating host cells. Highly mag-nified. From this internal part of the plant shortbranches grow out into the air, and these becomeswollen terminally into rounded segments, whichare in fact short zoosporangia. Instead of formingzoospores at once, they first fall off and thenthose that fall into water develop zoospores. FUNGI much as in the water moulds. As these struc-tures are very minute, a droplet on a leaf islarge enough for the germination of hundredsof the detached zoosporangia. Here again, thezoospores, after coming to rest, develop into newplants, which at once penetrate the host. Insome species the zoosporangia grow at once intoa filament, without forming zoospores. The sexual organs of downy mildews aremuch like those of water moulds, the differ-ences b
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectencyclo, bookyear1908
