31. In bryophytes, the sporophyte is a simple unbranched structure with a single spore-forming organ ( sporangium ). 32. These ferns are called " leptosporangiate " because their annulus around the sporangium , which ejects the spores. 33. To release its spores, a sporangium split into two'valves'along a thickened margin at the top. 34. Unlike other members of the Mucorales, " Cunninghamella " species produce only one spore in each sporangium . 35. In meiotic sporogenesis, a diploid spore mother cell within the sporangium undergoes meiosis, producing a tetrad of haploid spores. 36. This releases cytoplasm, which is used to glue the upper portion of the swelling containing the sporangium to the substrate. 37. As in all the tree ferns, the ring is oblique and complete, not interrupted by the foot of the sporangium . 38. At maturity the sporangium is topped by a flattish disk ( an operculum ) and releases its spores when this breaks up. 39. Two hyphae of different mating type encounter each other, and their tips undergo a haploid nuclei like those in the vegetative sporangium . 40. Ferns typically produce large diploid sporophytes with rhizomes, roots and leaves; and on fertile leaves called sporangium , spores are produced.
