Akebia quinata

Growing on a chain-link fence close to both the north and south gates is Akebia quinata (Houttuyn) Decaisne (family Lardizabalaceae), a twining vine from temperate eastern Asia. The genus Akebia originated from the Japanese name for this plant, and quinata refers to the palmately compound leaf, composed of five obovate to broadly elliptic leaflets. Another cultivated akebia, A. trifoliata, has three leaflets, but, par for the course, on A. quinata one can find five, three, or even four leaflets per leaf! Distinctive and characteristic is the emarginate (i.e., notched) leaflet apex, which also has a barely noticeable tip projecting from the midvein on the lower side.

Whereas dicotyledons typically have flower parts in multiples of fours or fives, Lardizabalaceae are trimerous (i.e., with parts in multiples of threes). Akebia, which flowers at MEMBG during March and April, has separate male and female flowers on the same plant (it is monoecious). An inflorescence has a few female flowers positioned beneath a raceme (unbranched stalk) of male flowers. Each flower is one color-a remarkable heliotrope (red-purple)! The female (pistillate) flower, two to three centimeters across, typically has three petal-like sepals, five or six (sometimes more) stick-like pistils, and minute staminodes (modified but sterile stamens) positioned between the pistil bases. The stigma has a very sticky exudate covering a minute opening in the pistil (it is unsealed)-extremely rare among angiosperms. The male (staminate) flower has three sepals with six stamens surrounding and hiding three diminuative, nonfunctional pistils (pistillodes) at the center of the flower. The chunky, "mezzalunate" stamens form a tight ring and release white pollen from the outward-facing anther sacs. At MEMBG we have not yet seen the Akebia fruit, which is a fleshy follicle that splits (dehisces) along the upper side and contains several hundred black seeds within white pulp.

Phytogeographers are intrigued by this small but old family because Lardizabalaceae has a remarkable disjunct distribution. Five genera occur in eastern Asia and the Himalayas, whereas Lardizabala and Decaisnea (formerly called Boquila) are native of faraway central Chile! Akebia quinata, sometimes called chocolate-vine, has escaped its Asian origin and domestication and now is naturalized in the eastern United States.

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