With the sun dropping lower and the air getting cooler and lighter, the best season for walking is fast approaching. On my city and country jaunts I usually find myself out all alone. Not that I'm antisocial or anything like that; just that I get sidetracked so easily that almost no one can stand walking with me.

Just the other day, for example, I'm strolling along a suburban street with a very stylish friend. We're on our way to lunch when we pass some old stones. They're overgrown by a dense thicket, and surrounded by a small canopy of trees. The leaves on one of the trees catch my eye.

Gabong! Like instant zombie!

The tree is a hiiragi, a native Japanese species in the Oleaceae or Olive Family. But the leaves are thick and stiff, with points so sharp they could easily be used as sewing needles. The impression is more of a holly than an olive. Indeed, the Japanese name for common holly is seiyo-hiiragi, seiyo meaning "western" and designating something occidental, especially from Europe or America. The similarities between holly and hiiragi, however, are superficial, and they are not closely related at all.

There's absolutely no way I can pass this tree by. I simply have to stop and press my finger against the wicked points on the leaves. Ouch! Fortunately for me, my friend is an former nursery school teacher, and is fairly tolerant of this sort of childish behavior.

But I soon notice that not all of the leaves are equally pointy. As I examine leaves on higher and higher branches, I find the number and sharpness of the points gradually decreasing. Eventually I convince my friend to sit on my shoulders. I lift her up to where she can reach even higher branches. By stretching her arms over her head she is able to pluck a few leaves with perfectly smooth edges.

Like, totally stoked!

Spikes on leaves are generally thought of as a countermeasure against browsing herbivores. But producing hard spikes requires extra energy, and a plant is thus motivated to keep them to a minimum.

Brachiosaurs being long extinct, and there being no giraffes, elephants or okapi in Japan, the highest point a tree here has to worry about is about two meters above ground, or as high as the biggest deer can reach. Above that, heavy armament is just a waste of valuable energy.

The hiiragi has deep spiritual associations here in Japan. Perhaps due to the wicked spikes, the tree has long been considered a charm against evil and black magic. Traditionally, hiiragi were planted as guardians in the northeast corner of a homestead or garden. In yin-yang geomancy, this is the kimon, or goblin-gate, the direction from which misfortune and evil is most likely to approach.

Another widespread custom is to stick a sprig of hiiragi, along with the head of a sardine, on the door at the time of the winter setsubun, which falls just before the start of spring in the traditional Asian lunar calendar. The rancid odor of the rotting sardine and the hiiragi's wicked spikes make an unbeatable tag-team for warding off evil and bad luck.

I lower my very patient friend back to the ground and we prepare to resume our progress. But alas? not to be!

Just as we're leaving, out of the corner of my eye I spot some bright orange color down near the base of the trees. Brightly colored objects, of course, can never be ignored. Down on my hand and knees, I push aside the briars and brambles, and there in a small, partially sunlit clearing is a patch of beautiful lilylike wildflowers.

But wait, at the base of each flower, below the point where the sepals and petals attach, and easily visible from the outside, is a beadlike protuberance. An inferior ovary! The plant is not a lily at all, but a spider lily, in the Family Amaryllidaceae. All Liliaceae or Lily Family plants have superior ovaries, which means the ovary is located above the line where the sepals and petals attach, and as such is always hidden inside the flower. Spider Lilies, in contrast, have these inferior ovaries.

This particular spider lily is called the kitsune no kamisori, or literally "the fox's shaving razor." At this time of year, the plant has no leaves at all, and is thus easy to mistake for a parasite. The spider lily's leaves, however, have simply wilted away. In early spring the plant sends out a dense cluster of long, thin leaves, the shape of which accounts for its peculiar Japanese name. For several months the spider lily photosynthesizes, creating energy and storing it in an underground root system. By midsummer, the leaves have disappeared, but there is enough energy stored up to fuel the flowers and fruits to follow.

My friend, maybe because she's wearing designer jeans and high-heel sandals, refuses to crawl down into the thicket to see the shaving razors. Not even an inferior ovary will tempt her. The closest she'll come is to sit on my backside and peer in over my shoulder while I enthusiastically show her the flower's six long stamens and single pistil.

Finally we disengage from the thicket. I brush the dust and grass from my clothes, and we prepare to pick up our lunchtime stroll. But just at that very moment. Huge spikes of purple pea flowers perched along the edge of the thicket. Yikes! The first kudzu blooms of the season.

I involuntarily start toward them, but something grabs the back of my shirt collar and yanks me away. I hear the staccato clackety-clack of high heels stamping angrily on the pavement.

Oh well. I guess the kudzu vines will be in bloom for quite a while yet.

Short is a naturalist and cultural anthropology professor at Tokyo University of Information Sciences.

(Sep. 2, 2010)