. Botany for high schools and colleges. Botany. 256 BOTANY. from the former ; in other species the plants are dioecious, and in them the antheridia produce motile spermatozoids, b} means of which the fertilization is effected. After fertilization â¢each oosphere becomes covered with a wall of cellulose and is thus transformed into an oospore. 340.âThe development of the sexual organs of AcMya, «ne of the genera of this order, is shown in Fig. 171, 6 to 10 ; at first there is a small pullulation upon the side of a filament, as at 6 ; this soon extends into a bag-like projec- tion (7), which is
. Botany for high schools and colleges. Botany. 256 BOTANY. from the former ; in other species the plants are dioecious, and in them the antheridia produce motile spermatozoids, b} means of which the fertilization is effected. After fertilization â¢each oosphere becomes covered with a wall of cellulose and is thus transformed into an oospore. 340.âThe development of the sexual organs of AcMya, «ne of the genera of this order, is shown in Fig. 171, 6 to 10 ; at first there is a small pullulation upon the side of a filament, as at 6 ; this soon extends into a bag-like projec- tion (7), which is readily seen to be a young oogonium; it continues to enlarge, while its protoplasm becomes more dense, and at its narrower part a second pullulation forms (frequently two), as shown at 8 ; when the larger part has enlarged somewhat more and become rounded, a partition separates it from the remainder of the filament, and from the young anther- id ium, as shown at 9; the ,_. _,^ protoplasm in the oogonium .^ ,(S^ " ,. forms several round massesâ ^â "^i^ " the oospheresâand by this time the terminal portion of the antheridium is cut off by a partition. In the monoe- cious species a tube is formed by the closely applied anther- idium, which penetrates into the oogonium through open- ings in it formed by the absorption of portions of its wall and comes in contact with one of the oospheres (Kg. 173). 341.âIn some cases, instead of the oogonia developing in the way described above, they are formed in the terminal part of a filament by one or more partitions arising in it; such oogonia are cylindrical or barrel-shaped, and sometimes several of them stand upon one another. The antheridia in the species which have such oogonia are developed from below the partition which cuts off the oogonium, and when there are several superimposed oogonia it actually happens. Fig. 172.âFertilization of the oospheres In .AMija, racenwsa. Each oogonium contains two oospheree. Ma
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectbotany, bookyear1888
