Angiosperms are perhaps best known for their beautiful flowers and their delicious fruit, which surrounds their seeds. They're actually also the most diverse group of seed-producing land plants. Angiosperms are generally classified based on how many cotyledons their seeds have. Monocots have one cotyledon, and eudicots have two cotyledons. You can see a monocot over here and notice how it just has one leafy bit to it, and over here, we have a eudicot. Notice how it has two leafy bits on its sprout. And yes, "leafy bit" is the technical term there. Now, you might be wondering why it's "eudicot," "eu" meaning true, and not just "dicot." The reason is the group actually used to be called dicots and included other species that have since been rearranged into other lineages. Those other major lineages are basal angiosperms and magnoliids. Now, let's take a look at the flower, the defining feature of the angiosperm.
The flower is the reproductive organ of angiosperms and has many parts to its anatomy. You've probably taken note of these if you've looked at flowers before, but you may not have known all the terms for each of the parts. To begin, there's the sepal, which, if you've ever seen a flower bud, is those green leaves that encase the little flower bud, and when the flower bud matures, they look like those green leafy bits underneath the petals. So right here, this part is a sepal. Now, we also have the petals; these are modified leaves that surround the reproductive organs of the flower. Their purpose is often to attract pollinators, which is why they have these beautiful colors and sometimes interesting patterns inside of them.
The stamen is the male part of the flower, the pollen-producing part, and is made up of the filament and the anther. You can see a stamen right here; this is the filament or the stalk. There's also one marked over here; this is our filament. And here we have the anther, that nub on the end. If you've ever had fresh flowers hang around your house for a little too long, all the stamens fall off, the anthers knock pollen everywhere, and it's like a huge mess. The trick is you got to pull them out before the flowers die.
The carpal is the female part of the plant, and some plants have multiple carpals. If a plant has multiple carpals, they are referred to collectively as the pistil. Now, the carpal is also made up of different parts, and you can see, we have the carpal right here. The top of the carpal, let me use a different color, the top of the carpal is referred to as the stigma. The portion that goes from the stigma down to the ovary is called the style. You can see the style is this portion here. The ovary is this lower portion that contains the ovules, which will become the seeds in the fruit. Now over here, we have another ovary, or I guess they're showing the stigma as well. So, technically, this is a full carpal, though the top of this image is a little cut off. So that's why it looks a little funny. But anyway, within the ovule, here is our embryo sac. It's basically the female gametophyte inside the ovule. And you can see here, a pollen tube is extending to it. And, of course, the fruit is formed from the ovary, the ovary of the carpal. Alright. With that, let's turn the page.
