Dorcas Speer Interviews Dr. Lois Tiffany (WOI News Clip 352)

Again Dr. Louis Tiffany from the botany and plant pathology department and I are down in Pamela woods and this is the same tree that we were talking about the last time and we had some more to say about it because we were talking at that particular time of the Opera of the leaves being opposite and the type of leaf and one hole this is this is one whole leaf that's right one entirely right but there are some other things that you don't have to necessarily have those leaves on that you shouldn't be that you could see that even if over winter time right now if we go back to this branch here where we broke one leaf off to take a look at it a little more carefully you can see that there's a nice neat break area here and this is where this leaf would have that leaf would have fallen off this autumn now this is called a leaf scar obviously enough and you can see the little bud right there just above the leaf scar and it'll be bigger by next fall but not much so now if you look back here on the older part of this branch if we get back into last well this is two year old area we're in here actually but you can see here is a leaf scar from last from two years ago and here even better on this branch that grew last year you can see these great big leaf scars and so in the winter even you can see that there are two leaf scars here opposite each other so this opposite an alternate business one can check out not only when the leaves are on the tree but via the leaf scars you can tell where they were in the winter time so this is a good good character to use any time of year actually all right now big question why is that little branch go off there why does a branch go off or twig or whatever you want to call it because that particular bud grew now okay many many trees have what we call apical dominance and an end bud will grow and the lateral buds the ones back along the side will remain dormant but if the top gets broken off say if we cut this one off here this bud which is right here at this knowed by this lease car would probably go ahead and grow if not this year next year so when you prune shrubbery in the yard or something like this you prune the ends off and then the the bud city normally wouldn't have grown otherwise we'll go ahead and develop well now this one doesn't prune them no this wasn't proved so this is just happen this is just natural something happened to us here this one did the one on this side didn't develop this one did uh-huh you notice there are lots of places back here along the they were see there but pear buds here right a pair of buds here now this has pretty distinct growth areas right this now they're very green branches right here are this year's growth and instead we say what time this was it's an ash all right the flex here on this stem are called lenticels and these are little Corky areas which permit the passage of gases from the cells inside the stem to the outside air and outside air gases into the stem and you'll notice there look different here you can still see them back here on the older branches also now this insect problem caused not to grow as much this would depend on the insect and on the particular plant this would vary with different combinations well now one thing I wanted to for us to go to this because we were talking about and not what it is particularly but you say that this this is the effect of an insect right this is where an insect is actually eaten out the the green cells of the leaf so that and these are the green cells are the ones that make the food for the tree so when they're evening if enough insects eat enough green cells then this tree would be in trouble another funny here where did it go did I step on it right here I think now that it looks like you know a little spider went by and left a little web I'm not an entomologist right but I think this is caused by an insect that's called a leaf miner and it tunnels actually through this through through the leaf and eats out again the green cells and so you see the little trails where it's journey through the central part of the leaf now I may be asking something that I shouldn't be asking you but as it goes from here across this main vein now did that cut off any of the food the traveling down to this vein back maybe maybe maybe maybe not I don't know really how my impression is that they just eat the the green cells which are relatively thin wall cells and the cells which actually transport materials are fairly thick walled but again I'm I'm talking about something I don't know a lot about now as far as other trees this is this is a puny one this is a but it's one that is of interest we were talking about poison ivy right and this last time that was last night and we were pointing out that poison ivy has three leaflets in each leaf well this is a box elder and it grows in the same kind of place as poison ivy does frequently and when you see this as a seedling tree with its three leaflets in each lake it sometimes can look very much like poison ivy the edges of the leaf are cut in very much the same way so does the box holder end up with the three leaves some box elders have three leaflets on each leaf as you can see this plant does fairly consistently some of them will have some threes some leaves that have three leaflets and some leaves that have five leaflets and so that there is no they're just this is just natural variation but it does I can definitely see why it would resemble the poison ivy now one of the interesting things about box elders serve a scrawny tree and this one is are almost only often they are but it you notice it has opposite leaves here again and it is actually in the maple group of plants but it's the only maple that we have in this part of the world are in this at least in the Midwest here that has a compound leaf all of our maples both hard maples and soft maples have simple leaves like the ones we've talked about before so this is is a peculiar maple know as I say this is one that looks like poison ivy what it's small but now we were talking about how poison ivy can grow and it's not always on the ground and this tree is a good example of how it can go up now the vine which you can see growing up that oak tree there is actually a Virginia Creeper vine but if we finally right but if we couldn't see the the leaves on it right now the vine itself the stem growing up there looks very much like a poison ivy vine and grapevines obviously out in the woods look very much like this also and don't use them too don't use it to swing on no well you get that poison ivy from the bark or does it have to be from the leaf or do you know you can you can get it from any part of the plant even the roots but you have to come actually into into contact with it I mean just walking by the tree right something like this would not be a problem in contact with the roots or with with the Sam or with the leaves right and this has to again finish this section at least and our guest has been again Dr. Louis Tiffany from the plant botany plant pathology department and maybe the next time we'll go on campus on some of the unusual trees fine thank you again we have with us Dr. Louis Tiffany of botany and plant pathology and the last time we were talking in the woods we promised that we talk more about leaves but we have discovered a leaf here that we better talk about first we're getting poison ivy we think you know the leaves over there I think are the ones that cause a lot of mothers and children to wonder if it's poison ivy now that is or is not poisoned this one you see has five leaflets they're all attached at one common point here onto a petiole onto a stem which goes down to the main stem now I'm not going to pick the poison ivy like that but it has three leaflets with which are attached in the same way coming in to a common point and the edges are very similar on the two but this business of three and five is quite significant now both of these plants both Virginia Creeper with the five leaflets in poison ivy with the three will be on the forest floor like this crawling along growing along they may occur as vines growing up on houses or on trees or they may look like short shrubs somewhat upright maybe two anywhere between two and four feet high so both the Virginia creeper and the poison ivy plant are alike in growth habit and they both obviously occur in the same kind of habitat same kind of places now I noticed that you were quite willing and I'll be daring enough to get a finger this close but now actually is it poisonous if you don't touch it or is that debatable depending upon the sensitivity of the person usually you have to actually come in contact with it except when you have poison ivy material that is in a fire if you're having a picnic fire somewhere or clearing an area in the woods if you get poison ivy material then the compound that people are sensitive to is volatile and it will be in the smoke one way people can contact it without actually touching the plant mm-hmm well now onto other leaves but just be careful about this one we'll watch this one now this leaf is I think it different tree but it has some of the same sort of edge as one of the trees the other day right it looks very much like the both the iron wood and the heck berry that we were talking about the other day and it has the same kind of leaf in that it is a simple leaf one flat green part one petiole and when we take a look at the stem here there is a leaf here a leaf here one at each node learnings point on the stem so and we said that there are plants where there is there are two leaves attached at one point here so we just will start from this one again and then this is basswood incidentally it's called also linden tree these are the same in same tree and it has it's a very common tree in the slopes here in the woods and often grows you can see there are two trunks there in a cluster and these are actually coming from the same root system and often you'll see different sized trunks coming up from the same root system so you get what looked like a whole cluster of trees but they're actually part of the same one so this this doesn't branch after it once it has a central trunk like some of the trees that may go up and then have their branches that actually it almost branches from the root system almost and this is one of the things that makes it perhaps a little more difficult in terms of lawn trees and things of this sort alright now maybe this was on the other and I didn't get it that look the little green fella over there that little green bump is the bud now this will be for next year's leaves and stem would come from and by the by this fall this one that which is bright green right now will be a sort of a coral pink color and so the winter buds or when when the buds go into winter they are actually a sort of a bright red and they're very handsome but it's it's a much more prominent on this it shows much better on this tree now is that unique for this tree or is it just the time of the year they're a little older than when we were looking at them last and also this one has bigger buds so it's got two things going for it all right all right now with this one in mind let's move over here and take a look at this maple now this one this one is different this one is different this is one of the maples this is so-called hard maple and as you can see at each node back here on the stem there are two leaves here coming off in this plane to here and the the basal part of the petiole here tends to to sort of sheath around the stem sort of encloses it much more than the other things we were looking at and you'll notice the leaf itself is a very different pattern and it has each one of these big areas here is called a lobe and so this individual this is a still simple leaf but each the leaf has three lobes on this particular one we're looking at and it doesn't have one big central vein that's right we can see this perhaps a little bit that's a little friend see this better on the reverse side of the leaf here you can see that there are our three large veins in fact there are a couple of ones which almost qualify as being as big rather than having one main midrib vein as on the leaves we've been looking at before so the vein pattern is quite different - and is characteristic of this particular kind of tree here again this hard maple and the basswood would be trees which we'd commonly find on slopes here in central part of Iowa like the woods were here in here today know now one other thing before we go to the other though okay now on the other we had the little buds but now this doesn't have nearly the prominent buds that the other one did and it's exactly the same time of the year okay now this one they're down in there and if we took the broke the petiole back we could see them nestled right in here where the petiole attaches onto the stem but they haven't developed nearly as much they won't be as big by next fall either now beginning right here is this year's growth right this much stem is this year's growth how much do they usually grow here or did it varies a great deal in individual trees and on different parts of the same tree mm-hmm this is down here in the shade so I'm sure if we you know but climbed up to the top of the tree we could find some that were much larger even is that a disease that's an insect now these are opposites but now that that one right there has opposites too and they look a little bit different all right now you're right you can see on the branches here maybe we can see it on this one very nicely there are two leaves here two here two here and but this much is one leaf on this right and this much is one leaf here right and you can see here again they're small but there's a bud right down there and this is the way we tell that this much I'll break this one off so we can take a look at it is one entire leaf now this is the petiole still but each one of these flat green parts which are separate would be individual leaflets so this is a so-called compound leaf because it has more than one flat green part and more than that it's called a pinnacle a compound leaf because there are leaflets attached here here and here so they're attached at different places on the stem now these are all important term terms if you're going to be looking up in the tree book for identification and this sort of thing right one of the first things a tree book will will ask you about in terms of the plant you're looking at is whether it has simple or compound leaves and so this is one of the one of the beginning steps if you missed that step and we'll have to get the details of that particular type of tree at another time our guest has been Dr. Louis Tiffany was a botany plant pathology department at Iowa State and we will continue perhaps another day