. Botany for high schools. Botany. place, there may be little or no seed or fruit developed, but when cross-pollination takes place an abundance of seed is formed. Even when pollen from the same and from a different flower is de- posited on the stigma, the pollen from the dif- ferent flower prevails. Cross-pollination is im- portant for the plant, since it insures greater T,, , , ^ ,^lf' u . r , visfor and 2:reater plas- The pendent flower of Yticca. showing position of sta- o o r mens and the ribbed ovary.— After Riley and Trelease. ticity in the offspring which make it better fitted to survi
. Botany for high schools. Botany. place, there may be little or no seed or fruit developed, but when cross-pollination takes place an abundance of seed is formed. Even when pollen from the same and from a different flower is de- posited on the stigma, the pollen from the dif- ferent flower prevails. Cross-pollination is im- portant for the plant, since it insures greater T,, , , ^ ,^lf' u . r , visfor and 2:reater plas- The pendent flower of Yticca. showing position of sta- o o r mens and the ribbed ovary.— After Riley and Trelease. ticity in the offspring which make it better fitted to survive in the struggle for existence. Still there are flowers in which the usual method of pol- lination is a close pollination. 284. Cleistogamous flowers.—Close pol- lination always takes place in cleistogamous flowers, of course if left to themselves. Cleis- togamous flowers are those which remain closed during the . process of pollination and fertilization. The violet is an excellent ex- ample. The showy flowers which are so conspicuous rarely develop seed. The greater quantity of seed is formed in flowers which are ilot showy and which are covered by the soil or leaf mold. They remain closed, and the pollen from the stamens is shed on the stigma of the same flower. 285. Pollination of the yucca by the moth Pronuba.—This is a remarkable case of close pollination brought about by an ^^"^ insect. The pollen is somewhat sticky and without some aid. section of an ovary of Yncca, showing the tunnel-shaped stig- matic opening (5), and the rows of ovules attached to the wall (o).— After Riley. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Atkinson, George Francis, 1854-1918. New York, H. Holt and Company
Size: 1001px × 2496px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1910
