Eurya japonica

Bryant is both the author and photographer for today’s entry. He writes:

Today’s image was taken in the David C. Lam Asian Garden, here at the UBC Botanical Garden. This dioecious evergreen shrub is native to temperate and tropical Asia (China, Japan, India and Malaysia). I was tipped off to go look at this plant by Douglas Justice (Associate Director and Curator of Collections at UBCBG). At first I had trouble finding the plant as it was slightly hidden behind a couple rhododendrons but I definitely had no trouble smelling it. Eurya japonica gives off a pungent aroma that could be described as metallic or zinc-like mixed with hints of ammonia and carrion, which I became familiar with while taking this image. This member of the Pentaphylacaceae grows to about 3m high. Plants have serrated leaves that appear in a herringbone formation. For another image of the branch/flower morphology and some interesting information on its taxonomic relationships, see the previous BPotD post on Eurya japonica.

Eurya japonica is known to be sexually dimorphic, meaning male and female plants are morphologically different in additional ways beyond the physical structure of the reproductive organs. Sexual dimorphism is fairly common among dioecious plants, and when dimorphism involves defense mechanisms we tend to think primarily of leaves, thorns and prickles (vegetative tissues). However, there have been an increasing amount of studies on defense mechanisms against florivory (flower-eaters). Eurya japonica is the subject of one such study concerning the chemical defense of its female flowers; see: Tsuji, K. and Sota, T. 2010. Sexual differences in flower defense and correlated male-biased florivory in a plant-florivore system. Oikos, 119: 1848-1853. doi: 10.1111/j.1600-0706.2010.18585.x.

In this case, the male flowers were observed to be eaten much more frequently than the female flowers by the florivorous larvae of the geometrid moth Chloroclystis excisa. This phenomenon was observed both in the wild and under controlled experimental conditions. In the wild, adult moths only deposited their eggs on male flowers. When eggs were deposited on the female flowers/buds of Eurya japonica in captivity, all of the resulting larvae that fed on the calyx of the female flower did not survive. This is believed to be due to higher concentrations of phenolic compounds and condensed tannins that occur in the female flowers. Generally, florivory of male flowers seems to be more prevalent than florivory of female flowers among sexually polymorphic plant species. Although there are some theories as to why this may be, there is much to be learned about the co-evolution of flowers and florivores and what truly makes sex-based selection occur.

For more reading relating to Eurya japonica and geometrid moth interactions see:

Kaoru Tsuji & Teiji Sota. 2011. Geographic variation in oviposition preference for male and female host plants in a geometrid moth: implications for evolution of host choice. Entomologia Experimentalis et Applicata. 141: 178-184.

For further reading on male-biased herbivory, see:

Lorne M. Wolf. 1997. Differential Flower Herbivory and Gall Formation on Males and Females of Neea psychotrioides, a Dioecious Tree. Biotropica, 29: 169-174.

Krupnick, G. A. et al. 1998. Floral herbivore effect on the sex expression of an andromonoecious plant, Isomeris arborea (Capparaceae). Plant Ecology. 134:151-162.

Eurya japonica

9 responses to “Eurya japonica”

  1. Walt

    Mine that I’ve grown from seed is approaching 6m now in some 25 years (Seattle). It’s a male but I haven’t noticed any lepidopteran predation but will start more intensive searching.

  2. michael aman

    What recommends eurya as a horticultural specimen plant? Certainly not the fragrance. Yet there must be gardeners who love it for other traits.

  3. Mary Yee

    Beautiful image. I wonder if the blue tint on the pedicels and sepals is real or an artifact of the light and the camera.

  4. Bryant

    Mary- The image was shot in the shade with a 100mm macro lens, the slight blueish hue is likely a bit of chromatic aberration…

  5. Katherine Gordy Levine

    This is one of the sites I will be promoting at my Facebook 76th Birthday Party and Book Launch Bash.
    The book? Easy Exercises to Tame Bad, Mad, and Sad Feelings. “Being with Beauty” is one of the exercises.
    Hope any of you on Facebook will join me there.
    Brian and all the photographs who post here, you have helped me stay emotionally strong. Thank you all. Katherine Gordy Levine

  6. elizabeth a airhart

    daniel do you all know phil gates and his digital botanic garden site tis lovely prof at durham univeristy in scotland lots to look
    at and read writes for country garden more then one site now
    lovely silver bells in above picture thank you bon bon

  7. Daniel Mosquin

    I think it’s a white-balance issue, because of the colour cast from the shade. I’ll update with an adjusted version.

  8. Steve Edler

    Durham is in England. Any designs the Scots may have had on it were dealt with by Edward I in his discussions with William Wallace. But, ’tis true, Phil Gates is lovely, even if he looks a bit like a pirate with that eyepatch.

  9. Mary Yee

    So interesting to learn about chromatic aberration, thank you, Bryant. (The aberration lent a lovely feature to the photo, though.)

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