Field of Science

Friday Fabulous Flower - Basal Angiosperm Flower at the stage of seed dispersal

An old, but very sturdy TV antenna tower (remember those?) stands at the corner of our house, and it seemed like a good idea to plant a vine next to such a good climbing structure. The vine is Kadsura japonica, magnolia vine, and it occupies an interesting phylogenetic position that you are probably not aware of. Angiosperm taxonomy used to be easy: monocots and dicots. Monocots are still pretty easy, but not dicots. At the base of the flowering plant "family" tree are three lineages that have the most ancient common ancestries with the rest of the flowering plants. And one of these three lineages includes the Schisandraceae, the Schisandra family, which has two genera: Kadsura and Schisandra. The flowers of this species have either lots of pistils or leafy anthers, but not both, surrounded by a perianth not differentiated into petals and sepals, and all the parts are spirally arranged. Each pistil develops into a red fruitlet borne upon a much elongated receptacle (think long skinny strawberry). In the two flowers shown, at the stage of seed dispersal, you can see both the mature fruitlets and abortive ones that didn't get pollinated. The red fruitlets are edible, although pretty tart, and if enough of them could be reached (the vine is now 15+ feet above the roof of our house) some basal angiosperm jelly would be in the offing. Soon a flock of cedar waxwings, or some other dinosaurian relative (how appropriate for such an ancient lineage!) will appear, and the fruitlets will disappear. Although sensitive to late spring frosts, the vine is hardy in zone 5 and probably in zone 4 too. Just the thing to hide that old antenna tower!


Frederick B. Essig said...

I hate to see this fine post sitting with no comments. As a botanical educator myself, I appreciate good, educational botanical content on the web. One of my special interests is botanical terminology, and I am probably out of the mainstream quite often. For example, I find the common usage of the term “pistil” unsettling, because it is used for both individual carpels and for structures consisting of several fused carpels. The difference is important, especially when discussing ancient angiosperms with separate carpels (apocarpous), like the Schisandra and Magnolia illustrated in your post. Carpels are the individual, ovule-containing chambers that evolved from folded structures in the first angiosperms. The preferred technical term for all the carpels in a flower, whether separate or fused together, is gynoecium (Greek for “ladies room”). If we must use the older term “pistil,” I’d prefer to use it only for a unit of several fused carpels, or at least to specify “unicarpellate pistil” if it is a single carpel. But then why not just say carpel? OK, enough botanical nit-picking for today. Keep up the great posts!

The Phytophactor said...

As one botany professor to another, one hates to pull rank, especially as a floral morphologist, but here's the problem. If you describe a gynoecium as "multicarpellate" you still have to indicate whether or not they are fused or separate. But when you say multi-pistillate you know each pistil is composed of a single carpel. However it is true that if a flower has a single pistil, you do not know if it consists of one or more carpels.