microsporangiumn.

1862 F. Currey tr. W. Hofmeister On Germination Higher Cryptogamia xi. 331 By careful dissection of microsporangia under the microscope..I succeeded in separating entire the inner cell membranes of the microspores from the glutinous contents of the microsporangia.

1875 A. W. Bennett & W. T. T. Dyer tr. J. von Sachs Text-bk. Bot. 396 If a microsporangium is about to be formed, each of the mother-cells is broken up into four tetrahedral spores, which all develope into microspores; in the macrosporangium, on the contrary, the mother-cells remain, with one exception, undivided.

1887 H. M. Ward tr. J. von Sachs Lect. Physiol. Plants xlii. 746 The..micro-sporangia become expelled.

1911 Encycl. Brit. XXIII. 122/1 The microsporangium, which produces a large number of microspores (pollen-grains), is termed the pollen-sac.

1959 A. S. Foster & E. M. Gifford Compar. Morphol. Vascular Plants xix. 495 This well-marked outer layer of the microsporangium wall is usually designated as endothecium.

1992 M. Ingrouille Diversity & Evol. Land Plants 115 In most gymnosperms the pollen sacs (microsporangia) are grouped together on the abaxial surface of special scale leaves called microsporophylls.