11 This Anthoceros gametophyte… shows three antheridia… Antheridium sterile jacketUpper EpidermisSpermatogenic tissueThallus parenchymaLower EpidermisRhizoids
12 Here is the best I could find on the web to show the archegonium which is embedded in the hornwort gametophyte thallus.Apical CellSterile Jacket CellsNeck Canal CellsVentral Canal CellEgg Cell
13 The artist would lose one point above…why? What are some missing items as well?The “spore mother cell” is better known as sporocyte!We shall find out why this is so, as we proceed to more-derived plants.
17 The Anthoceros sporophyte foot is embedded in the gametophyte. The sporophyte seta has an intercalary meristem.GametophyteThallusIntercalaryMeristemFootGametophyte rhizoids
18 The Anthoceros sporophyte has evolved guard cells and stomata. While initially dependent on the gametophyte, it carries out its own photosynthesis.The sporophyte may continue to grow while the gametophyte degenerates.Two apo-morphies are shown here… which?
20 The Anthoceros sporangium is linear and indeterminate in size. It is surrounded by a layer of cortex and epidermis.sterile jacketsporocyteThe sporocytes divide by meiosis, producing meiospores.The tri-radiate marks and surfaces that the tetrad of spores impress upon each other are shown here.
28 Here is the cross section of a maturing part of the “horn”…the Anthoceros sporophyte. The sporophyte shows a cutinized epidermis, a step up from the gametophyte.In the center of the sporophyte, you can find the hydroids and leptoids!Spores appear in tetrads (the four meiotic products) of which three are generally in any plane of sectionThe cortex cells are responsible for the photosynthetic support for the sporophyte.
29 The sporophyte maturing to shed spores to the wind
30 The Anthoceros sporophyte matures from tip to base shedding almost unlimited spores due to intercalary meristem at base.
31 The tip of the Anthoceros sporophyte matures first, shedding the spores to the wind.
32 The Life Cycle of Anthoceros SYNGAMYzygoteSporophyteGametophytesporangiumsporocytesporesgametangiagametesgerminationmitosisdifferentiation1N2NMEIOSIS