Oak Hybridization   Robert Leverett   Jan 17, 2007 06:13 PST  ENTS,  One question that comes immediately to mind is about oak hybridization.  This past Saturday, John (John Davis, Conservation Director of the Adirondack  Council) took Monica and me to a conservation property he helps oversee to inspect what has been reported as black maple and yellow chestnut oak (chinkapin oak). I had a devil of a time identifying the species that John thought had been identified as chinkapin oak. We couldn't find any acorns to examine. After consulting many books, the species appears to be a cross between a swamp white oak and bur oak. I couldn't ID it as quercus muehlenbergii, although at one point I thought I had. Lee, (or any of the rest of you) have you encountered any oaks up your way that appear to be hybridizations between those two species? A book that have on oaks explains that within a genus, they are notoriously promiscuous (naughty oaks). Bob      Robert T. Leverett Cofounder, Eastern Native Tree Society Re: Oak Hybridization   wad-@comcast.net   Jan 17, 2007 07:40 PST  Bob Below is a list of the hybrid oaks on the Pennsylvania Big Tree list. The one that mostly resembles Chinkapin oak to me, is the Jack oak. A cross between White Oak and Chestnut Oak resulting in many tiny rounded lobes. Oaks are very naughty, and I have a hard time telling scarlet and red apart around here sometimes, or black and red, or Pin and Scarlet etc. The acorns are the key if you can find one! Leana Oak Quercus x leana (Q. imbricaria x Q. velutina) Bebb Oak Quercus x bebbiana (Q. Alba x Q. macrocarpa) Bender Oak Quercus x benderi (Q. rubra x Q. Coccinea) Bartram Oak Quercus x heterophylla (Q. phellos x Q. rubra) Jack Oak Quercus x jackiana (Q. alba x Q. montana) Saul Oak Quercus x saulii (Q. alba x Q. prinus) Scott Back to Scott   Robert Leverett   Jan 17, 2007 08:03 PST  Scott, Thanks. I noticed the Bebb Oak (alba and macrocarpa). Can you describe that hybride to me? Does it have the mossy cup acorns or something in between? Hey, I think we're going to have to assemble a representative from each of the oak species and their current hybrids and give them a good talking to. Want to deliver the sermon? I'm told that the overlords of the Ents frown on such promiscuous goings-on as the oaks are givin to doing. Must be a sure sign of Armageddon when the lion lays down with the leopard and all the oaks congregate at the local pub. Bob Re: Back to Scott   wad-@comcast.net   Jan 17, 2007 09:40 PST  Bob The only thing I know about hybrids is they tend to produce acorns in about 7 years, where straight species can take 25 years. Apparently the acorns are edible and sweet. I don't know what they look like. Bob do you have measurements for the National Champion Black oak that are more recent than 1989? Scott Oak Hybrids   Edward Frank   Jan 17, 2007 20:31 PST  Oak Hybrid Listings Sylvics of North America, Volume 2: Hardwoods Burns, Russell M., and Barbara H. Honkala, tech. coords. 1990. Silvics of North America: 1. Conifers; 2. Hardwoods. Agriculture Handbook 654. U.S. Department of Agriculture, Forest Service, Washington, DC. vol.2, 877 p. --------------------------------------------- White Oak (Quercus alba) In addition to the type variety, two varieties of Quercus alba have been named: Q. alba var. repanda Michx. and Q. alba var. latiloba Sarg. Seven hybrids are recognized: Quercus x jackiana Schneid. (Q. alba x bicolor); Q. x bebbiana Schneid. (Q. alba x macrocarpa); Q. x beadlei Trel. (Q. alba x michauxii); Q. x faxonii Trel. (Q. alba x prinoides); Q. x saulli Schneid. (Q. alba x prinus); Q. x fernowii Trel. (Q. alba x stellata); Q. x bimundorum Palmer (Q. alba x- robur). White oak also hybridizes with the following: Durand oak (Quercus durandii), overcup oak (Q. lyrata), and chinkapin oak (Q. muehlenbergii). ----------------------------------------------- Swamp White Oak (Q. bicolor) Two forms of swamp white oak have been described: a mesophytic form with leaves that are green and velvety on the lower surface and a more xerophytic form with leaves that are white-tomentulose beneath. The following six hybrids with swamp white oak are recognized: Quercus x jackiana Schneid. (Q. bicolor x alba); Q. x humidicola Palmer (Q. bicolor x lyrata); Q. x schuettei Trel. (Q. bicolor x macrocarpa) (1); Q. x introgressa P. M. Thomson (Q. bicolor x muehlenbergii x prinoides) (11); Q. x substellata Trel. (Q. bicolor x stellata); Q. x nessiana Palmer (Q. bicolor x virginiana). Swamp white oak also hybridizes with chestnut oak Quercus prinus) and English oak (Q. robur). ------------------------------------------------- Scarlet Oak (Q. coccinea) Scarlet oak hybridizes with black oak (Quercus velutina), producing Q. x fontana Laughlin, and with bear oak (Quercus ilicifolia), producing Q. x robbinsii Trel.; it also hybridizes with pin oak (Q. palustris). ----------------------------------------------- Quercus falcata Michx. var. falcata Southern Red Oak (typical) Nine hybrids of southern red oak have been recognized (10). They are crosses with Q. ilicifolia, (Q. x caesariensis Moldenke); Q. imbricaria (Q. x anceps Palmer); Q. incana (Q. x subintegra Trel.); Q. laevis (Q. x blufftonensis Trel.); Q. laurifolia (Q. x beaumontiana Sarg.); Q. marilandica; Q. nigra (Q. x garlandensis Palmer); Q. phellos (Q. x ludoviciana Sarg.); Q. velutina (Q. x wildenowiana (Dippel) Zabel, Q. x pinetorum Moldenke). ------------------------------------------------- Quercus falcata var. pagodifolia Ell. Cherrybark Oak ------------------------------------ Turkey Oak (Q. laevis) Turkey oak hybridizing with southern red, bluejack, laurel, and water (Q. nigra) oaks results in the following hybrids (15): Quercus falcata (Q. x blufftonensis Trel.), Q. incana (Q. x asheana Little), Q. laurifolia (Q. x mellichamp Trel.), and Q. nigra (Q. x walteriana Ashe). ---------------------------------------------- Laurel Oak (Q. laurifolia) In the past, laurel oak and diamond-leaf oak have been considered by some to be two varieties or even separate species (11). Trees first recognized as laurel oak were on well-drained sandy banks of streams whereas diamond-leaf oak was found on poorly drained flat sites (5). Burke concluded that laurel oak itself is of hybrid origin, intermediate between and derived from willow oak and water oak (2,3). His work is based on a leaf-shape index applied to seedlings grown from acorns collected on the North Carolina Outer Banks and at Chapel Hill, NC. He states that laurel oak is not found outside the ranges of the two supposed parental species. This would appear true based on most published maps showing the range of willow oak available in 1961 and 1963, when Burke's publications appeared. However, the range map for willow oak published in 1965 (14) shows willow oak to be absent in the southeastern half of Georgia and peninsular Florida where laurel oak grows in abundance, leaving some doubt that laurel oak is the hybrid between willow and water oak (14). The following hybrids with Quercus laurifolia as one parent have been recognized (11): Quercus falcata Q x beaumontiana Sarg.), Q. incana Q. x atlantica Ashe), Q. laevis Q. x mellichampii Trel.), and Q. marilandica Q. x diversiloba Tharp ex A. Camus). ------------------------------------------------------- Overcup Oak (Quercus lyrata) Wide differences in quality of overcup oak occur over its range-generally the better quality is found in its northern and eastern range. These differences, however, are probably due to response to site and seasonal flooding patterns rather than to genetic differences. Limited studies of juvenile variation within a small geographic area have not provided any evidence of genetic variation among localities. Hybrids Quercus lyrata hybridizes with Q. alba; Q. durandii; Q. bicolor (Q. x humidicola Palmer), Q. macrocarpa (Q. x megaleia Laughlin); Q. michauxii (Q. x tottenii Melvin); Q. stellata (Q. x sterrettii Trel.); and Q. virginiana (Q. x comptoniae Sarg.) (8). A cross between Q. lyrata and Q. virginiana is reported to be promising for propagation and dissemination (10). This hybrid is a semievergreen and has a higher growth rate than either parent. However, its vegetative propagation has presented problems. ---------------------------------------------------------- Bur Oak (Quercus macrocarpa) A northern form of bur oak, Quercus macrocarpa var. olivaeformis, has been recognized (5). Acorns of this form often germinate in the spring following seedfall rather than soon after falling, and germination is improved by stratification. Acorn size is about half that of the southern form, and the cup is much thinner and smaller. Cleaned seeds average 595/kg (270/lb) compared to only 165/kg (75/lb) for the typical species (16). Where the two forms are found in the same locality, as in eastern Nebraska, the typical bur oak is more common on the moister sites (5,13). Varietal crosses occur in such areas. Photoperiodic ecotypes of bur oak have also been recognized. In one study, shoot growth of a more northerly seed source was about two-thirds of that of a more southerly seed source under short days; under long days, shoot growth of both sources was nearly equal (24). Hybrids Bur oak has been known to hybridize with nine species as follows: white oak, Q. x bebbiana Schneid.; swamp white oak, Q. x schuettei Trel.; Gambel oak (Q. gambellii); overcup oak, Q. x megaleia Laughlin; swamp chestnut oak, Q. x byarsii Sudw.; chinkapin oak (Q. muehlenbergii), Q. x deamii Trel.; English oak (Q. robur); post oak, Q. x guadalupensis Sarg.; and live oak (Q. uirginiana). The cross with white oak, Q. x bebbiana, Bebb oak, is one of the most frequent of the white oak hybrids and is widespread within the overlapping ranges of the two species (9). The hybrid formed with Gambel oak, a western species, is somewhat unusual in that the two species do not now have overlapping ranges (15). ------------------------------------------- Swamp Chestnut Oak (Q. michauxii) Swamp chestnut oak hybridizes with Quercus alba (Q. x beadlei Trel. ex Palmer); Q. lyrata (Q. x tottenii Melvin); and Q. macrocarpa (Q. x byarsii Sudw.) ---------------------------------------------- Quercus montana Willdenow, Mountain chestnut oak, rock chestnut oak The four species of the chestnut oak group in eastern North America ( Quercus montana , Q . michauxii , Q . muhlenbergii , and Q . prinoides ) are somewhat difficult to distinguish unless careful attention is paid to features of leaf vestiture and fruit and cup morphology. [http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=233501064] ------------------------------ Chinkapin Oak (Q. muehlenbergii) Chinkapin oak intergrades with dwarf chinkapin oak (Quercus prinoides) and both have been recognized as varieties of the same species by some authors. Dwarf chinkapin oak, however, is commonly a low-growing, clump-forming shrub, rarely treelike, and is a separate distinct species. Two recognized, named hybrids of chinkapin oak are Q. x introgressa P M. Thomson (Q. muehlenbergii x Q. bicolor x prinoides), and Q. x deamii Trel. (Q. muehlenbergii x macrocarpa). Chinkapin oak is also known to hybridize with white oak (Q. alba); Gambel oak Q. gambelii); and dwarf chinkapin oak (Q. prinoides) (6). ---------------------------------------------- Water Oak (Q. nigra) There are no reported racial variations of water oak. It hybridizes with other oak species as follows (3): Quercus falcata (Q. x garlandensis Palmer), Q. incana (Q. x caduca Trel.), Q. laevis (Q. x walteriana Ashe), Q. marilandica (Q. x sterilis Trel.), Q. phellos Q x capesii W Wolf), Q. shumardii (Q. x neopalmeri Sudw.), and Q. velutina (Q. x demarei Ashe). ----------------------------------------------- Nuttall Oak (Q. nuttallii) No racial variations or hybrids have been reported. North of Memphis, TN, this tree is easily confused with Q. palustris (pin oak). --------------------------------------------- Pin Oak (Q. palustris) No races or genetically distinct populations have been defined within pin oak, but the existence of such populations has been suggested based on differences in flood tolerance and resistance to iron chlorosis (3,9). Five hybrids of pin oak are recognized (17): Quercus x mutabilis Palmer & Steyerm. (Q. palustris x shumardii), Q. x vaga Palmer & Steyerm. (Q. palustris x velutina), Q. x schochiana Dieck (Q. palustris x phellos), Q. x columnaris Laughlin (Q. palustris x rubra), and an unnamed hybrid with Q. coccinea. ---------------------------------------------- Willow Oak (Q. phellos) No racial variations of willow oak are known, but the following hybrids are recognized (14): Quercus phellos x nigra (Q. x capesii W. Wolf); Q. phellos X velutina (Q. x filialis Little); Q. phellos x ilicifolia (Q. x giffordii Trel.); Q. phellos x rubra (Q. heterophylla Michx. Q; Q. phellos x falcata (Q. x ludoviciana Sarg.); Q. phellos x shumardii (Q. x moultonensis Ashe); Q. phellos x marilandica (Q. rudkinii Britton); Q. phellos x palustris (Q. x schociana Dieck.). --------------------------------------------- Chestnut Oak (Q. prinus) No races of chestnut oak are known. Chestnut oak hybridizes with Quercus alba (Q. x saulii Schneid.); Q. bicolor; Q. robur (Q. x sargentii Rehd.); and Q. stellata (Q. x bernardiensis W. Wolf) (19). ---------------------------------------------------- Northern Red Oak (Q. rubra) Several traits related to geographic origin were identified for northern red oak in a 14-year provenance test in the North- Central States. Time of flushing is earliest for trees of northwestern origin. The trend is then eastward and southward. Autumn leaf coloration is earliest for provenances from northern latitudes and then progresses southward. Provenances from regions at the western edge of the northern red oak range, where periods of high summer temperatures and drought are common, survived better under such conditions than other provenances. Much variation in height growth was present and performance of the provenances was not consistent in all tests. The only consistent difference was the slower growth of the northern provenances in areas farther south. The within-family variation was so great it obscured any real differences in geographic origin (15). Races The nomenclature for northern red oak was confused for some time. The scientific names Quercus borealis Michx. f. and Q. borealis var. maxima (Marsh.) Sarg. were adopted after 1915 by some authors, but in 1950, Quercus rubra L., the name in universal use before 1915, was restored (17). Hybrids Northern red oak hybridizes readily with other species in the subgenus Erythrobalanus and the following hybrids have been named: Quercus x columnaris Laughlin (Q. palustris x rubra); Q. x fernaldii Trel. (Q. ilicifolia x rubra); Q. x heterophylla Michx. f. (Q. phellos x rubra); Q. x hawkinsiae Sudw. (Q. velutina x rubra); Q. x riparia Laughlin (Q. shumardii x rubra); and Q. x runcinata (A. DC.) Engelm. (Q. imbricaria x rubra). ------------------------------------------------------ Shumard Oak (Quercus shumardii) Shumard oak has two varieties-Quercus shumardii Buckl. var. shumardii (typical), and Q. shumardii var. texana (Buckl.) Ashe, Texas oak, found in central Texas, including the Edwards Plateau, and in southern Oklahoma in the Arbuckle Mountains. Shumard oak hybridizes with Quercus hypoleucoides; Q. imbricaria Q. x egglestonii Trel.); Q. marilandica (Q. x hastingsii Sarg.); Q. nigra (Q. x neopalmeri Sudw.); Q. nuttallii; Q. palustris (Q. x mutabilis Palmer & Steyerm.); Q. phellos (Q. x moultonensis Ashe), Q. rubra (Q. x riparia Laughlin); and Q. velutina Q. x discreta Laughlin) (4). ------------------------------------------------------ Post Oak (Quercus stellata) The great variation in post oak and its tendency to hybridize creates a number of varieties and hybrids. The following hybrids with Quercus stellata have been recognized (10): Q. alba (Q. x fernowii Ti-el.); Q. bicolor (Q. x substellata Trel.); Q. durandii (Q. x macnabiana Sudw.); Q. havardii (unnamed); Q. lyrata (Q. x sterrettii Trel.); Q. macrocarpa (Q. x guadalupensis Sarg.); Q. minima (Q. x neo-tharpii A. Camus); Q. mohriana (unnamed); Q. prinoides (Q. x stelloides Palmer); Q. prinus (Q. x bernardiensis W. Wolf); Q. virginiana (Q. x harbisonii Sarg.). ------------------------------------------------------- Black Oak (Q. velutina) Although races of black oak have not been identified, a study of 14 populations from southern Indiana to northern Michigan revealed morphological differences. Northern populations had smaller acorns with less cup cover, lighter yellow inner bark, smaller winter buds, and a more branching growth form than southern populations (21). Black oak hybridizes readily with other species in the subgenus Erythrobalanus. The following named hybrids with Quercus velutina are recognized (19): Q. coccinea (Q. x fontana Laughlin); Q. ellipsoidalis (Q. x palaeolithicola Trel.); Q. falcata (Q. x pinetorum Moldenke); (Q. x willdenowiana (Dippel) Zabel); Q. ilicifolia (Q. x rehderi Trel.); Q. imbricaria (Q. x leana Nutt.); Q. incana (Q. x podophylla Trel.); Q. marilandica (Q. x bushii Sarg.); Q. nigra (Q. x demarei Ashe); Q. palustris (Q. x vaga Palmer & Steyerm.); Q. phellos (Q. x filialis Little); Q. rubra (Q. x hawkinsiae Sudw.); Q. shumardii (Q. x discreta Laughlin). --------------------------------------------------- Live Oak (Quercus virginiana) Two varieties of live oak are recognized: Quercus virginiana var. fusiformis (Small) Sarg., Texas live oak, and Q. virginiana var. geminata (Small) Sarg., sand live oak. Live oak hybridizes with Quercus bicolor (Q. x nessiana Palmer); Q. durandii; Q. lyrata (Q. x comptoniae Sarg.); Q. macrocarpa; Q. minima; and Q. stellata (Q. x harbisonii Sarg.). ----------------------------------- Say you are looking to see whether a tree is a white oak or a red oak. Identification is complicated by the occurrence of hybrids, which often have quite variable leaves. All species are inclined to hybridize except that white oaks do not hybridize with red oaks. Since many hybrids lack fruit, it is a good idea to turn to neighboring trees with acorns. When these fertile trees have been named it is often possible to recognize a hybrid in respect to the two parents that are involved. Hybrids can often be recognized as hybrids if they cannot be "keyed out" and/or do not match any photographs and descriptions. Re: Welcome to new members and question for Lee   William Morse   Jan 18, 2007 05:02 PST  *Swamp white and bur oaks hybridize readily here in western NY (Q. x schuettei *Trel.). When doing vegetative inventories, both state and federal agencies generally ask that hybrids be listed as seperate species, so I have never had a need to learn the common name of this species. Maybe Schuetts Oak? Good luck, Travis RE: Oak Hybrids   Willard Fell   Jan 18, 2007 05:50 PST  GOOD GRIEF CHARLEY BROWN.... I was just getting to feel pretty smug, I had gotten a laser and was well on my way to working the kinks out of the big tree records and then you hit me with this. I have suspected as much, but most of the taxonomists I have dealt with like to put species in neat little boxes. There are several trees I have struggled with, one has been listed as a national champion Durand Oak for 15 years and I have a stack of letters this thick every year it comes out in print. Depending on what authority has looked at the leaves/acorns/twigs it has been variously id'd as Bluff Oak, Durand Oak, Delta Post Oak, Sand Post Oak and lord knows what else. Isn't there a Bastard Oak out there... ;-) My head is spinning just reading the list of possibilities. I guess I should be thankful many of the oaks listed in your post are not native to GA. Hopefully none have slipped off down here to the creek bank with my great Live Oaks. RE: Oak Hybrids   Edward Frank   Jan 18, 2007 06:17 PST  Will, The literature states that pretty much all of the white oaks will hybridize with each other, all of the red oaks will hybridize with each other, and the chestnut oaks will mix with some as well. There may be newer listings somewhere, but the Silvics Manual was pretty complete. It provides a basis for a consistent nomenclature of the crosses which seemed to ba question in previous posts. Things might still not be clear, but this was something to contribute to the discussion. Ed The Red Oaks   Doug Bidlack   Feb 02, 2007 13:39 PST  ENTS, we have been talking a bit about how to tell some of the red oaks apart. I also belong to the International Oak Society and this very question came up not too long ago about the red oaks of the Chicago area. The following paragraphs are from Matt Strong of Kansas. I'd defer to Dick on this one, but from my limited observations of Q. coccinea and Q. ellipsoidalis I agree completely with Dick, that it appears they are 2 seperate and good species. And after hearing Andrew Hipp and Jeanne Romero-Severson presentations at the IOS conference I'm thoroughly convinced that this is the case. It seems they are sometimes difficult to seperate morphologically, but here's a few differences that seem to be relatively consistent as far as I can tell. Some of these have been already noted in the other emails. Hill's Oak tends to be a smaller growing tree than Scarlet Oak. Hill's Oak is a more Northerly growing Oak than Scarlet Oak and Hill's Oak tends to keep a "skirt" of dead branches on the lower trunk while Scarlet Oak doesn't. Scarlet Oak will often have a ring of pits on the apex of the acorn, while Hill's Oak does not usually have these pits. The leaves on Scarlet Oak tend to be larger than the leaves on Hill's Oak. The acorns on Scarlet Oak tend to be fatter/wider than those on Hill's Oak. The acorn cap on Scarlet Oak is usually larger(especially wider) than the acorn cap on Hill's Oak. The scales on the acorn cap tend to be glossy and glabrous(hairless) on Scarlet Oak, while they tend to be puberulent(finely hairy) and not glossy on Hill's Oak. This makes the cap on Hill's Oak feel smoother when feeling it from the top down, while the cap on Scarlet Oak tends to be rougher feeling(more uneven). Maybe Dick or someone else might know of more differences, or have some corrections in my preliminary observations. Also, I think it's usually quite easy to tell Q. rubra from Q. ellipsoidalis(and Q. coccinea). Q. rubra has a dull leaf surface, while Q. ellipsoidalis(and Q. coccinea) have a glossy leaf surface. The sinuses on Q. rubra are almost always only as deep as 1/2 the distance to the midrib or less, while on Q. ellipsoidalis(and Q. coccinea) they are usually deeper(often times more than 3/4 the distance to the midrib). Also, the lobes on Q. rubra taper(become narrower) towards their ends, while Q. ellispoidalis(and Q. coccinea) has lobes which usually expand(become wider) towards their ends. The acorns on Q. rubra are usually significantly larger than those on Q. ellipsoidalis(and Q. coccinea) and more oblong (fatter) than those on Q. ellipsoidalis(and Q. coccinea). So, I think there are more than enough differences to make it relatively easy to seperate these 2 species. Black Oak(Q. velutina) is also relatively easy to seperate from Hill's Oak. Black Oak has dark gray or black deeply fissured blocky bark, while Hill's Oak(and Scarlet Oak) doesn't have bark as dark or deeply fissured. Occasionally it seems you can find a Scarlet Oak with bark almost as deeply fissured as Black Oak, but again it's usually noticeabley lighter in color. Black Oak usually has a slightly larger acorn cap than Hill's Oak(but not as large as Scarlet Oak). Also, the scales on the acorn cup of Black Oak are loose at the tips, especially around the rim of the cup, while they are tightly appressed on Hill's Oak(and Scarlet Oak). But the easiest, quickest way to seperate Black Oak from most all other Oaks, including Hill's Oak(and Scarlet Oak) is by looking at the buds. The buds on Black Oak are much larger than those on Hill's Oak or Scarlet Oak(usually twice as big or more). The buds on Black Oak are also uniformly pubescent(hairy) and silvery in color, while the buds on Hill's Oak(and Scarlet Oak) are dark reddish brown in color and glabrous (hairless) except for the apex(sometimes starting near the middle) where they are often pubescent, although they're never pubescent on the lower half of the bud. more red oaks   Doug Bidlack   Feb 02, 2007 13:46 PST  ENTS, here is some more great info on Northern Pin/Hill's Oak and Scarlet Oak. It is from Andrew Hipp. The research we've done on this to date suggests that most of the trees in the Chicago region that have been referred to Q. coccinea are in fact Q. ellipsoidalis. There are a few populations that seem to be true Q. coccinea, but very few. The data on vPlants do not reflect our current understanding, but within the next few months we'll be annotating these sheets to reflect what we know now. It's worth noting that E.J. Hill deposited some specimens as Q. coccinea b/f he decided they should be teased apart into the new species (Q. ellipsoidalis). That said, the EJ Hill collections on vPlants that are annotated as Q. coccinea were so annotated by Richard Jensen, who knows these species better than anyone else. My opinion is that Q. ellipsoidalis and Q. coccinea are separate taxa and that the latter is pretty rare in the Chicago area. I'd be happy to show you some data if you are interested (ahipp at mortonarb dot org -- we have a paper on this in press and another to be submitted soon). As far as the Q. rubra / Q. ellipsoidalis distinction, I agree that the bark character can be misleading. You are best off using apical buds, leaf morphology, and acorns if you can get your hands on them. Re: The Red Oaks   Steve Galehouse   Feb 02, 2007 14:59 PST  An additional comment regarding the red oaks is the nomenclature of /Quercus rubra/, Northern Red Oak. Old texts list it as /Quercus borealis/, with two primary "varieties", /Q. borealis borealis/, and /Q. borealis maxima./ These two varieties look very distinct to me, with /Q. borealis borealis/ having much smaller acorns with a deeper cup, much more deeply fissured bark, a more northerly range, and a smaller, scrubbier habit when compared to /Q. borealis maxima/(which is the commoner type, and I believe what most people think of as /Q. rubra. /For me at least, these two types are as or more distinct than /Q. velutina/ compared to /Q. coccinea. /Steve Re: more red oaks   Jess Riddle   Feb 02, 2007 15:48 PST  Doug, Thanks for posting this information. I've never been in the range of Q. ellipsoidalis, but if I ever am, I now stand a much better chance of not mis-identifying it as scarlet oak. Do you know what the "vPlants" referred to is? Is there a site online where I can read more similar descriptions? Jess RE: more red oaks   Doug Bidlack   Feb 02, 2007 20:13 PST  Jess, I think vplants just refers to vascular plants and it is part of a virtual herbarium of the Chicago region by Morton Arboretum. I just checked it out and they have photos of herbarium specimens of all kinds of plants. The description is just from an oak discussion group that you can easily join. Go to http://www.saintmarys.edu/~rjensen/OakDiscussion.htm and follow the directions. The group is not nearly as active as this one, but if you have any oak questions someone can probably answer them for you. Doug RE: The Red Oaks   Steve Galehouse   Feb 02, 2007 20:22 PST  Doug- The variety Q. borealis borealis is what I encounter in central Ontario, and occurs in xeric habitats, and is the only oak I've observed in that area; "regular" red oak(borealis maxima) occurs in more mesic habitats generally here in Ohio, and becomes a much larger tree, rivaling sycamore and cottonwood in size. Steve -----Original Message----- From: Doug Bidlack Sent: Friday, February 02, 2007 11:05 PM Subject: RE: The Red Oaks Steve, this is interesting. I'll have to find out more about these varieties. Do you notice a difference in habitat between these two varieties? Doug Michigan Champ Scarlet Oak   beth koebel   Feb 03, 2007 21:43 PST  Doug and the rest, I emailed the coordinator for Michigan Big Tree List and he told me that you had the right tree and that it is a hybrid between scarlet and northern red oaks (Quercus X benderi Baenitz). Scarlet oak terminal buds and Northern Red oak leaves. Beth Oak hybrids and intergeneric hybrids   Steve Galehouse   Feb 04, 2007 07:20 PST  The discussion regarding oak hybrids has been very interesting, and I thought I would bring up a topic that is curious from a taxonomic viewpoint. From what I know, none of the red oak types(Erythrobalanus) will hybridize with any of the white oak types(Lepidobalanus), although species within each group hybridize freely with others of their group. A similar pattern is seen in the maples, with the even more sections or subgenera displaying hybrids within the section but not among the sections, with red and silver hybridizing but never red and sugar, or the milky-sap Eurasian species hybridizing within their series(Acer platanoides x truncatum as an example) but not among the species in other series. Same with the five-needled pines and two-needled pines. But the curious thing is the number of intergeneric hybrid that can be found---Cupressus x Chamaecyparis; Sorbus x Aronia(and Malus, Pyrus, Crataegus); Fatsia x Hedera; Franklinia x Schima, and I’m sure there are many others. This implies these separate genera are more closely related than some species within a genus. I have always thought the generic level to be more exclusive as far as hybridizing compared with the specific level within a genus, and yet that’s not the case with oaks, maples, and pines at least. Obviously the plants “know” what they’re doing, so then our methods of taxonomic categorization must be somewhat limited or artificial. I now this post might be off-topic for ENTS, but I think it is still interesting. Steve Galehouse Resource for those confusing oak ID's...   Brandon Gallagher   Jun 05, 2007 13:14 PDT  Hey ENTS, This is mostly in regards to posts from a while ago discussing the difficulties in IDing oaks, esp. natural hybrids... I'm at the Nat. Oak Wilt Symposium down in TX and just met a researcher, Kevin Nixon from Cornell Univ, who did his PhD on the phylogeny of the Quercus genus. Very interesting talk on distribution and diversity of the oaks and their relatives. He went over many diagnostics for seperating species and when I cornered him after he said he would be delighted to help with many pesky ID issues that were discussed via ENTS. I don't have his contact handy but should be easily obtained from the net. -bg Brandon M. Gallagher Technical Support ISA Certified Arbortist #MN-4086A Rainbow Treecare Scientific Advancements 2239 Edgewood Ave S   Home