I am interested in identifying seedlings in the forest floor but I am currently concerned about the difficulty of the taxonomy in this life stage of plants. Is there any ID key or manual ? Is it hard or easy ? Thank you!
Tree seedlings can be hard to ID. Make sure you do not assume species based on proximity to adult trees. Do mention this information in your labels. You may have to mark some of them by genus name followed by spp. or add a note to the label that it is putatively a species, perhaps based on what kinds of mature trees are close and have the same leaves. Be sure to include notes on what is growing around them and soil/drainage conditions if you can. Sometimes things like vein patterns on mature leaves (if certain of the genus and if there are definitive differences in vein arrangements within that genus), stoma position/patterns/shape on mature leaves, cross section arrangements of xylem and phloem in stems and leaves, and bud shapes and scale patterns can help. There are also patterns of raphides and druses to consider but they can vary a lot among individuals even among the same kind of tissue, and are not always present in an individual. I do not know of a particular manual but you may be able to find tree sapling keys from USDA foresters for local regions within or adjacent to your larger area. DNA bar coding may also be very helpful, though bar codes are only as good as the material and considerations that went into them. Not everyone reporting bar codes gives sufficient consideration to how truly representative they are of the variation in a taxa, or with similar taxa. Others are very meaningful. You may also have problems identifying saplings as a result of hybridization. Be aware of how common that is for your region and the genus. Winter botany manuals often have information on bud scale patterns. If the species you are seeing fruit young and retain such material in the season you collect in, you may get lucky and find seeds or flowers or floral buds. Sometimes internode patterns and internode cross sections are also useful. Make sure that the layout of leaves that you see are fully extended, avoid leaf or floral whorl interpretation based on immature material that has not finished expanding along a branch sufficiently to really see how they are arranged. You may need to bring some of your material to a larger herbarium than the one you work in locally, to compare your putative findings to the variation found in a particular taxon. Hope this helps.
For hardwoods, you can often find the seed still attached to the seedling, then look for seeds on the tree for comparison :)
Miriam Kritzer Van Zant Dear Miriam, thank you for you answer! It clarified a lot of my possibilities. I am interested in making a phytosociological study in the regenerative stratum of pine and hardwood stands, and therefore I would need to identify at least part of the under/midstory. I will be collecting during the summer and I am currently thinking of how I could make species ID fast and precise enough to get a good representation of the community... Maybe switch to saplings in the midstory could be an alternative ? I think that saplings might be easier to ID.
Unfortunately, barcoding is not a financially possible option, although I believe it would be great to have access to it. I will keep an eye on the traits you mentioned and search for the manuals from USDA. Thank you again ! :D
Andrew Paul McKenzie Pegman Dear Andrew, thank you for your answer! I will definitely pay attention to it on my hardwood sites.
I recommend Andrew Pegman's answer also. However, it will probably frequently mean destruction of such young seedlings if they are dug up to see the attached seed, even if you try to replant them. So only try this if there are a lot of individuals that appear the same. By the way, cotyledyon shape may get you into some families at least. The usual leaf characters of leaf edges, smooth or specific patterns of dentation, arrangements and kinds of hairs and glands, the shape of leaf tips, etc. will help to identify some taxa though not all. I meant to say before that cross sections of nodes as well as of internodes may give additional information if you have a good key. There are also keys that paleobotanists use of the arrangements of cells within wood that might help, though not every place has them. You really need to spend some time in the herbarium, and with keys that botanists find dependable for certain taxa, and see if the characters of interest separate a certain group of taxa or not. If you are a student, you might be able to get a grant to cover the cost of reagents, pipette tips, and a minIon system to check bar codes. The units alone cost about $1,000.00. There are you-tube videos to show you the tricks of cleaning and using them. You need to be careful never to put air into the system or you will need to replace most of it. They can be held in the palm of your hand, and hook up to any computer or laptop with sufficient ram (at least 16 GB) to run the programs that go with them. You have to weigh the cost of the method against the time it takes, as well as the quality of using that method for a particular group.
if you spend enough time out there you will surprise yourself at how good you can ID things at all life stages. Some can get grass ID to species shortly after fire so you should be able to get some hardwood species (not very diverse compared to other groups) down to the lowest possible taxonomic level.
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