![Text-book of botany, morphological and physiological. Botany. FlG. 377.—A pollen-sac oiAlthaa rosea seen from the side, m the archesporium; B transverse section of an anther- lobe showing the two pollen-sacs, m Text-book of botany, morphological and physiological. Botany. FlG. 377.—A pollen-sac oiAlthaa rosea seen from the side, m the archesporium; B transverse section of an anther- lobe showing the two pollen-sacs, m](https://c8.alamy.com/comp/RPXH3F/text-book-of-botany-morphological-and-physiological-botany-flg-377a-pollen-sac-oialthaa-rosea-seen-from-the-side-m-the-archesporium-b-transverse-section-of-an-anther-lobe-showing-the-two-pollen-sacs-m-the-mother-cells-of-the-pollen-in-a-still-united-into-a-tissue-in-b-already-divided-each-into-four-pollen-cells-the-tapetum-of-the-pollen-sac-each-anther-lobe-consisting-of-two-pollen-sacs-is-here-borne-on-a-long-branch-of-the-filament-lobes-each-nucleus-forming-the-centre-of-one-of-the-lobes-by-the-ingrowth-of-the-thick-wall-of-the-mother-cell-a-simultaneous-formation-of-RPXH3F.jpg)
Text-book of botany, morphological and physiological. Botany. FlG. 377.—A pollen-sac oiAlthaa rosea seen from the side, m the archesporium; B transverse section of an anther- lobe showing the two pollen-sacs, m
![Botany of the living plant. Botany. THE STAMEN AND POLLEN-SAC 247 drying as the anther ripens is that their thin outer waUs shrinlc, while the thick inner wall retains its form. Botany of the living plant. Botany. THE STAMEN AND POLLEN-SAC 247 drying as the anther ripens is that their thin outer waUs shrinlc, while the thick inner wall retains its form.](https://c8.alamy.com/comp/RDY80X/botany-of-the-living-plant-botany-the-stamen-and-pollen-sac-247-drying-as-the-anther-ripens-is-that-their-thin-outer-waus-shrinlc-while-the-thick-inner-wall-retains-its-form-the-result-of-the-shrinkage-of-the-outer-side-of-the-fibrous-layer-will-naturally-be-to-reduce-the-curvature-of-the-convex-sporangia!-wall-and-the-slit-gapes-widely-tig-192-b-the-dusty-pollen-grains-are-then-readily-removed-there-are-various-differfences-in-detail-of-the-dehiscence-of-anthers-particularly-in-highly-specialised-flowers-but-in-all-ordinary-flowers-where-the-pollen-is-dry-and-powdery-the-way-i-RDY80X.jpg)
Botany of the living plant. Botany. THE STAMEN AND POLLEN-SAC 247 drying as the anther ripens is that their thin outer waUs shrinlc, while the thick inner wall retains its form.
![Lily anther, transverse section, showing pollen sacs | 2009 Photomicrography Competition | Nikon's Small World Lily anther, transverse section, showing pollen sacs | 2009 Photomicrography Competition | Nikon's Small World](https://www.nikonsmallworld.com/images/photos/2009/_photo800/16563_1_Sloss.jpg)
Lily anther, transverse section, showing pollen sacs | 2009 Photomicrography Competition | Nikon's Small World
![Botany for agricultural students . Botany. STAMEN 461 Stamen. — The stamen (microsporophyll) has its pollen sacs (microsporangia), Botany for agricultural students . Botany. STAMEN 461 Stamen. — The stamen (microsporophyll) has its pollen sacs (microsporangia),](https://c8.alamy.com/comp/RDCY22/botany-for-agricultural-students-botany-stamen-461-stamen-the-stamen-microsporophyll-has-its-pollen-sacs-microsporangia-usually-four-in-number-joined-into-the-struc-ture-called-anther-the-pollen-grains-microspores-are-numer-ous-in-each-sac-and-are-formed-before-the-flower-opens-like-the-spores-of-gymnosperms-pteridophytes-and-bryophytes-they-are-formed-by-special-cells-known-as-mother-cells-of-which-there-are-many-in-each-pollen-sac-as-shown-at-a-in-figure-408-these-mother-cells-also-divide-by-the-reduction-division-that-is-by-the-kind-of-cell-division-in-which-the-da-RDCY22.jpg)