I'm doing some amateur botany, and I was keying some plants in the Brassicaceae (Cruciferae) family, which requires detailed information about the seeds of the plant. My question is, in a seed, how can one identify features such as:
- Endosperm (when present)
- Accumbency/incumbency of the cotyledons with respect to the radicle (in dicots)
It also seems like the key parts of the seed will be within the seed coat; it's not always obvious how to remove this seed coat, or what methods exist. Are there resources for this sort of thing?
As a more concrete example, I've identified this Cardamine hirsuta from my backyard, but I'd like to verify some features of the seeds. Unfortunately, the seeds are very tiny, as this microscope photo of the silique shows, and the features are non-distinct.
Flora of North America provides these details for the Cardamine genus:
Seeds uniseriate, flattened, usually not winged, rarely margined or winged, oblong, ovoid, or globose; seed coat (smooth, minutely reticulate, colliculate, or rugose) mucilaginous or not when wetted; cotyledons accumbent, rarely incumbent
How can I figure out from dissection whether the cotyledons are accumbent or not? At least, that's the sort of question I'd like to be able to answer.