Introduction to structural and systematic botany, and vegetable physiology, : being a 5th and revedof the Botanical text-book, illustrated with over thirteen hundred woodcuts . FIG. 517. Ovary of a Buttercup, divided lengthwise, to display its ascending ovule. of Buckwheat, with an erect ovule. 519. Same of Anemone, with a suspended ovule. 298 THE coat: this appears as a circular ring around the base of the formingnucleus, which gradually becomes cup-shaped, and at length coversit like a sac, remaining open, however, at the summit. This orifice is called the Foramen,or Microp
Introduction to structural and systematic botany, and vegetable physiology, : being a 5th and revedof the Botanical text-book, illustrated with over thirteen hundred woodcuts . FIG. 517. Ovary of a Buttercup, divided lengthwise, to display its ascending ovule. of Buckwheat, with an erect ovule. 519. Same of Anemone, with a suspended ovule. 298 THE coat: this appears as a circular ring around the base of the formingnucleus, which gradually becomes cup-shaped, and at length coversit like a sac, remaining open, however, at the summit. This orifice is called the Foramen,or Micropyle. In far thegreater number of cases, asecond envelope is formed out-side of the first, beginning inthe same way, though alwayslater than the inner one, which,however, it eventually over-takes and encloses. Mirbelnamed the exterior coat of theovule the Primine, and the in-terior the Secundine,— names which are attended with the objec-tion that the secundine or inner coat is actually older than theprimine or exterior coat. Both sacs are open at the apex, and thesummit of the nucleus points directly towards the apertures. Theorifice or foramen of the primine or exterior integument is calledthe Exostome (or outer orifice) ; that of the interior or secundine,the Endostome (or inner orifice). The coats of the ovule andthe nucleus are distinct and unconnected
Size: 1630px × 1532px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorgra, bookcentury1800, bookdecade1860, booksubjectbotany
