The Cyme and the Bract: Other Lindens on the Tree Tour

Bracts are found on many plants and come in many different forms.

During bloom time lindens are easy to distinguish by their aroma and the clusters of small yellow flowers which resemble open tulips. After the flowers bloom and the seed, or nutlet, forms the linden can still be identified by the remains of the cyme, or flower clusters, and the bracts hanging along the branches. While still on the tree, bracts and cymes look like an extra, lighter green frill hanging below the leaves. 

The term bract was new to me, although on investigation, most of us are probably familiar with them in some form and think of them as “flower petals.” Instead they are specialized structures which protect the actual flowers of various species. Often, as in the case of poinsettias and dogwoods, we mistake the colored bracts for the flowers.  

Most of my resources say little about the cymes and bracts of the lindens. One website did talk about the bracts on lime trees, the British name for lindens. An interesting tidbit is that along with the flowers, bracts are harvested to make linden tea, which is known to help digestive disorders. It is also used as a sleep aid. The bracts alone may be made into a “beauty lotion” for cleansing the skin

Later in the year you have a clue you are under a linden when you find thin yellow leaves, which are actually bracts, under a tree. This year at least, these seemed to fall and scatter sooner than the actual leaves, but even when they are mixed with other leaves, they are distinctive in their thin, oval shape, rather like a tongue. 

There are a number of other linden trees on the City Park Arboretum tour. Most of them are either hybrids or cultivars. I can’t begin to tell a Greenspire Linden from a Redmond, although the first is a Tilia cordata and the latter is Tilia americana. According to Michael Dirr and Keith Warren in The Tree Book: Superior Selections for Landscapes, Streetscapes, and Gardens, each of these two trees, along with the many other cultivars, has its uses. The other cultivars found on the Arboretum tour are listed below with information from The Tree Book mentioned above. Numbers correspond to those on the Arboretum map.

C126 Tilia americana Sentry is narrower than most other versions and may have some resistance to Japanese beetles.

 C171 Tilia americana Redmond (C171) is said to be more urban tolerant that other lindens. 

Redmond Linden

C148 Tilia cordata Greenspire has the best pyramidal shape.

Greenspire Linden

C177 Tilia cordata Norlin is both a fast grower and cold hardy.

A83 Tilia x flavescens Glenleven is a hybrid between the American linden and the littleleaf linden and is known at the fastest growing linden hybrid. 

Glenleven Linden

E22 Tilia cordata Prestige. It seems little is written about this variety but it may be pollution resistant. 

C178 Tilia x flavescens Dropmore  The Dropmore linden is another hybrid which is viable to zone 2.

Dropmore Linden in bloom

C 149 Tilia cordata Fairview is said to have larger leaves.

Fairview Linden

 

 

 

Silver Linden. A Bee Killer?

Bees are often found dead or stunned underneath the silver linden.

One of the other unique lindens in the park is the Silver Linden (Tilia tomentosa.} This linden, or lime, is native to countries east of the Adriatic Sea, including Albania, Bulgaria,Croatia,Greece,Hungary, North Macedonia,Montenegro,Romania,Serbia, Slovenia,Turkey, and the Ukraine. The tree was introduced into Great Britain where it grows into north Scotland. This source  states the tree was used for lumber in Bulgaria and Romania. Another interesting use of the wood is in carvings found in Orthodox Greek temples.

paper on various species of linden in the Balkans mentions that Tilia tomentosa tends to reproduce via sprouts. This same paper recounts it is possible for some lime trees to live for a thousand years. It does not indicate which of the various species have reached this age, though. The University of Florida suggests propagation of this species is most often accomplished via cuttings as seed germination can take two years.

Oddly, the USDA calls T. tomentosa a native of Ontario. Most likely this is a mistake as most other sources list it as native to Asia and Western Europe exclusively. In North America this variety is hardy in zones 4-7 and was introduced in 1767.

Monumental Trees lists the tallest silver linden, a tree in Belgium, at 121 feet. The US list of Champion trees has no listing for Tilia tomentosa, although many sources, including Dirr and Warren’s The Tree Book:Superior Selections for Landscapes, Streetscapes, and Gardens, say it is an excellent street tree that is more resistant to aphids than other lindens, although other sources dispute this. This may also be true of Japanese beetles. It may be more drought and pollution resistant.This information seems to differ by the state which provides it and leads me to believe its properties vary with the environment it is in.

With the silvery underside to its leaves, many consider this a good shade tree with a shimmery effect in a breeze. Like most other lindens, bees are very attracted to its flowers from late June into July. Dirr and Warren, as well as others, report this might not be a good tree for bees as they are often found dead or stunned underneath them. Bumblebees are more prone to suffer than honey bees. Recently studies have been done to figure out if the problem lies with the biology of the bees or  has to do with the flower nectar. The conclusion reported in a Royal Society (2017) article is that further study is needed to determine the cause of death.

E17 Silver linden specimen Tilia tomentosa in City Park is a smaller tree located along the drive to the golf course parking lot. Part of the fire station can be seen in the background of this photo.

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Tilia tomentosa