The Encyclopaedia Britannica; .. A dictionary of arts, sciences and general literature . © Fig. 263. Fig. 262. flO. S6?—Transverse section of the fruit of the Melon iCurumu Iftto), Bhowlnitthe placentas pi. with the seeds attached to thetn. The thiee carrels fomilnetne pepo are separated by partitions cl. From the centre, processes s co tocircumference /. endinc In curved placentaries bcarinR the ovules. —Dinsrammnllc section of a compound unilocular ovary, in which thereare no Indications of partitions. The ovules o are attached to a free centralplacenta, which has no connection with
The Encyclopaedia Britannica; .. A dictionary of arts, sciences and general literature . © Fig. 263. Fig. 262. flO. S6?—Transverse section of the fruit of the Melon iCurumu Iftto), Bhowlnitthe placentas pi. with the seeds attached to thetn. The thiee carrels fomilnetne pepo are separated by partitions cl. From the centre, processes s co tocircumference /. endinc In curved placentaries bcarinR the ovules. —Dinsrammnllc section of a compound unilocular ovary, in which thereare no Indications of partitions. The ovules o are attached to a free centralplacenta, which has no connection with the walls of the ovary »long the walls. Cases occur, however, in which theplacentas are not connected with the walls of the ovary,snd form what is called central placenta (fig. 263).. This IS seen in many of the Caryophyllaccaj and (figs. 264, 265). In Caryophyllaceoe, however, while theplacenta is free in the centre, there are often traces foundat the base of the ovary of the remains of septa, as ifrupture had taken place, and, in rare instances, ovules arefound on the margins of the carpels. But in Priniulacese,Myrsinaceae, and Santalaceaj, no vestiges of septa or marginalovules can be perceived at any period of growth; the-placenta is always free,and rises in the centre ofthe ovary, and the partuncovered by ovules gra-dually extends into thestyle. Free central pla-centation, therefore, hasbeen accounted for in twoways ; either by suppos-ing that the inthe early state wereformed on the inarginsof carpellary leaves, andthat in the progress ot „„, „, .„ ,.,.,., , , i_ 1 ^*°- 264.—Pistil of Cei-aslium hirsutum cut- development these leaves vel-tlcally. o, unilocular or monolhecalseparated from them, ovary; p, free central placenta;
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectencyclo, bookyear1902
