Tilia – Latin name for the linden or lime tree (though not a citrus species), known in southern Sweden as linn and the origin of the name Linnaeus, whose original name was Carl von Linne’

Native range: N. America and Eurasia

Leaves:

• alternate and simple
• ~ oblique base, usually cordate
• usually serrate
• tertiary veins ladder-like between secondary veins
• deciduous stipules

Flowers:

• umbel-like clusters attached to a thin, narrow bract
• 5 sepals
• 5 petals
• green to yellow
• many stamens, grouped in 5 bundles
• 1 style

Fruit:

• globose
• nut-like
• stays attached to bract
• 1–3 seeds

Other characteristics:

• trees to 120 ft.
• deciduous
• fibrous bark
• large winter buds
• young twigs display zigzag pattern

Relevant info:

• flowers usually fragrant, attracting bees, wasps, flies and moths
• good honey plant
• wood used commercially for furniture, toys, boxes, musical instruments, clogs, beehives, etc.
• desirable because it is light, soft and resistant to splitting
• commercially harvested in Great Lakes region
• can live >1,000 yrs
• in Britain, known as “lime tree” from 1620s, earlier “line” (c. 1500), from Middle English “lynde” (early 14c.), from Old English “lind”
• in Central Europe, intensification of agriculture 5,000–7,000 years ago diminished abundance of native linden
• “Basswood” derived from “bastwood” [sic], in reference to the tough inner bark (“bast”) which has been used to make rope and mats

Ecology & Adaptations:

• over 2 dozen species, many of which can hybridize, primarily in temperate and subtropical regions
• pollination – volatile oils in flowers attract bees, wasps, flies and moths
• herbivore & microbial defense – compounds (e.g., tannins, flavonoids) produced as herbivory and pathogen defenses, but long-term survival depends on regenerative abilities
• adapted to wind – well-developed root systems that enable it to tolerate wind
• seed dispersal – nutlets are attached to elongated wings, which aid dispersal by wind
• in Arboretum collection:
  • T. mongolica (Mongolian linden) native to eastern China, including Inner Mongolia, and far eastern Russia
  • T. platyphyllos (Simmer linden)
    • platyphyllos = from Greek playts meaning ‘broad’ + phyllon meaning ‘leaf’ in reference to the large leaves
    • native to central and southern Europe (including Great Britain, where it is possibly only native in woods on calcareous soils) and, less commonly, southwestern Asia
    • found especially in lowland woodlands with shallow humus-calcareous soils in warmer climates, which are required for pollination to be completed
    • long-lived, able to survive more than 1,000 years
    • distinguished by hairy young stems and leaves
    • vegetative reproduction:
      • re-sprouts from root collar following damage or cutting
      • root suckers are produced as much as 5 m from parent tree
      • branches touching the ground may become rooted and produce vertical shoots
    • shade tolerant – invests in vertical growth over girth or forked stems, though some trees increase horizontal branching to increase light capture
    • drought tolerance:
      • stomatal closure decreases water loss through transpiration
      • naturally high starch concentrations may permit rapid degradation that leads to higher soluble sugar concentrations, which keeps water from flowing out of plant tissue
      • increases leaf and total xylem biomass and invests in invests in water transport efficiency by producing wider vessels at the stem apex to decrease the risks of cavitation (air bubbles)
    • wildlife – seeds are eaten by small mammals, but behavior of moles (digging and collecting seeds) can aid seed dispersal
  • T. americana (American basswood, American linden)
    • americana = reference to native territory of species in Eastern U.S.
    • native to Eastern U.S. and is one of 6 species that characterizes the Eastern Deciduous Forest ecoregion
    • found in both dry upland and moist, low woods
    • pollinated by bees
    • shade tolerance:
      • shade leaves are thinner than sun leaves, which minimizes investment in light-capture surface
      • stomatal density and size are lower on shade leaves, perhaps indicating less need to prevent water loss in cooler, less exposed conditions