This is a bit of a visual echo in response to the photomicrograph from Dr. Robin Young a few days ago. This is from a set of young ‘Robusta’ Japanese creeper (or Boston ivy, if you like) vines planted several years ago by one of the Garden’s inventive horticulturists. I suspect photographs like these (and there are many similar compositions to be made) will only be possible for the next few years, until the entire wall where these are planted is eventually covered with the much larger mature leaves (like the outfield walls at Wrigley Field).
Parthenocissus tricuspidata is native to China, Japan, Korea and Taiwan. An explanation of its name is available from the Freckmann Herbarium (Parthenocissus tricuspidata), while additional photographs and horticultural information can be read via the University of Connecticut Plant Database: Parthenocissus tricuspidata. Compared to the species, the cultivar ‘Robusta’ is supposed to have larger (mature) leaves and be a bit more of a vigorous grower.
Given a suitable surface, this deciduous vining species can attain heights of 30m or so. It does so through adhesion, whereby a modified tendril in the shape of a disc-shaped pad secretes a mucilage. In 1875, Darwin noted that “a 10-year-old branchlet with only one remaining adhesive disc attached to a wall could support a weight of 2 lb without the disc detaching”. Further tests have revealed that “on average, the disc can support a combined weight of stem, leaf, branchlet, and tendril which is 260 times greater than its own weight during the growth, and can sustain a maximum pulling force which is 2 800 000 times higher than that produced by its own weight (from the abstract of a 2010 paper by the authors of the paper cited below). Despite having been studied for centuries, the precise adhesion mechanism remains unknown (though calcium ions are suspected to play a role). In He, T. et al. 2011. Biological adhesion of Parthenocissus tricuspidata. Arch. Biol. Sci.,63(2): 393-398 doi:10.2298/ABS1102393H , the authors conclude “Understanding the super-adhesion mechanism of Parthenocissus tricuspidata is a prerequisite for bio-inspired design of adhesive materials, and more experimental and theoretical works are imperative to fully open this new research field”.