Tips for Lime ID in Herefordshire

Top tips for the two species, so that the more tricky hybrids can be more easily winnowed out.

SMALL LEAVED. Herbarium specimen. Note (1) thin petioles (leaf stalks) – these are often longer in proportion to the leaf blade than in the other species; (2) erect, multiple-flowered inflorescences. These are ‘good’ characters which along with other clues (small, round leaves with some showing the bunches of rusty hairs) certainly rule out large-leaved lime and arguably the hybrids too.
SMALL LEAVED on R (with large-leaved on L). Leaves from below. As in the previous photo, small-leaved has clearly more slender petioles which are hairless. These freshly emerged shoots have not yet developed the rusty colouration on their characteristic hair tufts but these can nevertheless be seen in the early stages of development. The leaf-toothing of small-leaved shows well here: acute and tapering to a short point but NOT drawn out into a very thin, millimetre-plus tip (‘apiculus’). Shape in lime leaves is not always diagnostic because of position on the tree, etc, but these small-leaved leaves are classic: beautiful heart-shaped leaves (latin epithet cordata = heart shaped) with length and breadth fairly similar.
SMALL LEAVED from Raddle Bank near Leysters. Classic small-leaved has noticeably small leaves (sometimes as small as a 50p piece), of a dark green, against which the flowers and especially their bracts stand out markedly, with an underside that is obviously bluish-green where the foliage is well-illuminated. These characters can all be seen by clicking on the image to enlarge it.
SMALL LEAVED is VERY conspicuous in June and July when its pale bracts and upward / outward-facing flowers colour the whole canopy from a distance. In Herefordshire’s hilly landscape where long views are common, this is a great time to note and flag woodland trees in your area for further study later. Large-leaved Lime also shows up in this way, but less so. Beware Sweet-Chestnut which can be even more conspicuous in this way (chestnut more likely as blocks in the woodland, lime as trees dotted about). Pic from Tintern Abbey.
LARGE LEAVED. Herbarium specimen. Note (1) the very acute leaf-toothing with the leaf tooth drawn out into a long, hair-like apiculus. Remember to hunt for well-lit leaf material! Also note (2) the few-flowered inflorescences – here very immature with 4 flowers, but some buds will fall leaving only 2-3 fruits as the year progresses. The larger, less neat leaves, shorter, thicker leaf stalks (petioles) with hairs that do not show well in this image, and shorter stalk to the bract all help shape the diagnosis.
LARGE LEAVED with small-leaved, showing detail of the petiole differences. These specimens are also freshly emerged. Note fatter petiole of large-leaved with individual, white hairs sticking out at right-angles to the surface (patent hairs), showing a nice comparison with the thinner, hairless petiole of small-leaved. This type of hairiness often extends onto the veins of the leaf underside – different from the rusty, bunched hairs of small-leaved which cluster most in bunches in gaps between the veins.
LARGE LEAVED. Note how freshly emerged leaf petioles with their patent hairs form a fuzz which catches the light. As the year moves on, some of the hairs wear off, and you may need a lens to check specimens that you suspect are large-leaved later into the autumn. Chanstone Wood.
LARGE LEAVED. Beautiful material from Downton Gorge. Note (1) small number of PENDENT flowers and (2) the very evident sharp-leaf toothing with each tooth prolonged into an apiculus (click to enlarge). Less reliable but here helping to confirm are the bracts of the inflorescence, which are almost stalkless.
LARGE-LEAVED showing the tendency of the upper leaf surface to be rugose – ie baggy between the veins like a Savoy cabbage. Nice toothing again.
LARGE LEAVED. Spanish material showing classic leaf-toothing, hairy petioles, few-flowered inflorescences, and last year’s fruit with strong ribbing and a pentagonal cross-section. These are very difficult to crush between the fingers
A lime seedling (thought a hybrid plant because of the tree underneath which it was growing). Visible are the unmistakable cotyledonary leaves (the first true leaves not yet emerged), which demonstrate lime’s now formal inclusion into the mallow family, many of whose members have palmate leaves like these. Near Bodenham, Herefordshire. Please report any limes reproducing by seed!

HYBRIDS. In areas where both species grow, natural hybrids will occur, though the situation is less hopeless than pessimists might think, as peak flowering time is earlier in Large-leaved by 15-20 days and in many sites the true species are readily identifiable. We still need to work out the prevalence of natural hybrids in Herefordshire. Because of back-crossing (introgression), hybrids are variable. Where species boundaries are drawn is a moot point when there might be 25% of one genome and 75% of another.

Hybridisation also occurs within the trees’ main range in continental Europe from where certain hybrids were selected and propagated clonally, especially in the Netherlands, to provide large numbers of plants for the fashionable avenues and walks of grand houses from the late 1600s onwards. This tradition continued into later centuries outwith grand country houses, presumably because the tree fared well in urban environments and the stock was available. Most of these trees belong to a single clone, correctly referred to botanically as Tilia x europaea L. var. europaea, by horticulturalists often as Tilia europaea Pallida, but, thanks to its abundance now widely and simply known as Common Lime.

There are thus 4 trees to get to grips with: Small-leaved Lime, Large-leaved Lime, wild hybrid Lime and Common Lime. These are their usual contexts:

Small-leaved: Old or replanted woodland, sometimes in hedgerows nearby, or planted in parkland and churchyards

Large-leaved: Similar to small-leaved, but rarer, and associated with limestone or calcrete and cornstone within the Old Red Sandstone. Perhaps more frequent as an avenue tree in Herefordshire. Still planted today

wild hybrid Lime: Old or replanted woodland, either alone or in the company of both or perhaps more commonly one parent. Flag the possibility of wild hybrid Lime in your records if there seems to be a mix of significant characters, eg bunches of rusty hairs in the vein axils AND many single, white hairs sticking out at right angles (patent hairs) from the main surface of the underside. Small-leaved is the commoner tree and you may sometimes encounter odd singletons in amongst fair numbers of that species which show at least some traits of Large-leaved, and which may be relicts of the Large-leaved genome. I have found puzzling trees like this at Badnage Wood near Tillington, and near Vowchurch, Whitfield and Dinmore Hill.

Common Lime: Older suburbs of towns, municipal parks, churchyards and the grounds of manor houses and stately homes (which often border on woodland!).

Common Lime: Note abundant epicormic shoots (fuzz at the base of the tree) and narrowly conical outline.

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