When you see a crack itâs important to determine where it is and how severe it is. In order to figure out whether itâs a big deal, you need to know what kind of foundation system you have. For this article Iâm going to talk about âpier and curtain wallâ foundations. This type of foundation is most common in the pre-1950 houses in Durhamâs in-town neighborhoods.
A gametangium (plural: gametangia) is an organ or cell in which gametes are produced that is found in many multicellular protists, algae, fungi, and the gametophytes of plants. In contrast to gametogenesis in animals, a gametangium is a haploid structure and formation of gametes does not involve meiosis.
Multicellular gametangia Plant gametophytes produce gametes within multicellular organs called gametangia. A female gametangium, called an archegonium, produces a single egg cell in a vase-shaped organ. The egg is retained within the base. Male gametangia, called antheridia, produce and release sperm into the environment. In many major groups of living plants, the sperm have flagella and swim to the eggs though a water film. Each egg is fertilized within an archegonium, where the zygote develops into the embryo.