. The elements of botany for beginners and for schools. Plants. SECTION 10.] PISTILS. 107 the midrib of the leaf,—no1 a scam therefore; bul al maturity many fruits, bucIi as pea-pods, open bj this dorsal as well as l>\ the ventral line. Placenta, a name given to the Burface, whatever it be, which bears the ovules and seeds. The name may be needless when the ovules grow directly on the ventral suture, or from its top or bottom ; but when there are many ovules there is usually some expansion of an ovule-bearing or Beed-bearing surface; as is seen in our Mandrake or Podophyllum, Fig. '62(1 309
. The elements of botany for beginners and for schools. Plants. SECTION 10.] PISTILS. 107 the midrib of the leaf,—no1 a scam therefore; bul al maturity many fruits, bucIi as pea-pods, open bj this dorsal as well as l>\ the ventral line. Placenta, a name given to the Burface, whatever it be, which bears the ovules and seeds. The name may be needless when the ovules grow directly on the ventral suture, or from its top or bottom ; but when there are many ovules there is usually some expansion of an ovule-bearing or Beed-bearing surface; as is seen in our Mandrake or Podophyllum, Fig. '62(1 309. A Compound Pistil is a combination of two, three, or a greater number of pistil-leaves or carpels in a circle, united into one body, at least. 326 327 328 829 by their ovaries. The annexed figures should make it clear. A series of Saxifrages might be selected the gynoccium of which would show every gradation between two simple pistils, or separate carpels, and their com- plete coalescence into one compound and two-celled ovary. Even when the constituent styles and stigmas are completely coalescent into one, the nature of the combination is usually revealed by some external lines or grooves, or (as in Fig. 328-330) by the internal partitions, or the number «if the placent;e. The simplest case of compound pistil is that 310. With two or more Cells and Axile Placentae, namely, with as many cells as there arc carpels, that have united to compose the organ. Fio. 326. simple pistil of Podophyllum, cut across. Bhowing ovules borne on placenta. Wiq, :vi7. Pistil of a Saxifrage, of two simple carpels or pistil-leaves, united at the base only, cul across both above and below. Fio. 328. Compound S-carpellary pistil of common St. JohnVwort, cut across. the three styles separate. Fio. 329. The same of shrubby St. John's-wort ; the three styles as well ai ovaries here united into one. Fio. 380. Compound8 carpellary pistil of Tradescantia orSpiderworl ; the three stigmas as well as style
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectplants, bookyear1887
