Discussion

Fern fossils are quite common. This one came from a coal mine in Pennsylvania.

Field Horsetail (tsukushi)

Fifteen species of horsetails are extant, one of which, the Field Horsetail, is one of this week's painting subjects. Field Horsetails are perennials that live in the entire arctic and temperate regions of the Northern Hemisphere, including Japan. It grows in limited areas of the Southern Hemisphere, too. They have extensive root systems from which grow two different types of vertical stems.

The first part of the plant to appear, in March, is the brownish stem in the middle of the picture above, a harbinger of spring to Japanese.

The stem is hollow, and like bamboo, has joints at intervals. The bulbish-shaped object at the top is a cone or strobilus, a mass of scales or bracts. That is where the reproductive organs are located. When ripe, massive amounts of very tiny spores are released, though most horsetail spread is directly from extensive root systems.

These fertile stems typically grow from 4 to 10 inches tall.

When the strobilus begins to wither, the green, sterile stem from the picture above appears. It, too, has nodes spaced along the stem from which needle-like leaves grow. The spacing of the nodes along the stem inspired an investigation by mathematician, John Napier, leading to his discovery of logarithms.

Photosynthesis occurs in these sterile stems, including on the stem itself. They grow from about 4 inches to 3 feet tall.

Tsukushi is eatable, but it contains thiaminase that can leach vitamin B from the body. It can be toxic to livestock that eat too much of it. Cooking destroys this substance. The fertile stem is best eaten before the strobilus ripens. The taste of the stem is mild and simple, except for the cones which are bitter. After the strobilus ripens, the flavor becomes unappealing.

At the top of the stem is a whorl of 3 leaves (fronds), each 2 or 3 times compound and generally triangular in outline. The leaf blade is 2 to 4 feet long and 1 to 3 feet wide. The leaves are held nearly erect to almost horizontal, parallel to the ground.

Bracken spores develop on the underside of leaflets in lines bordering the edges.

When bracken first emerge from the ground, leaves are curled into balls called fiddleheads because of their resemblance to the scrollwork at the end of violin handles. Bracken fiddleheads are a little different from those of other ferns. In the photos below, the first are fiddleheads from Ostrich Ferns, and the second are of Bracken fiddleheads.

While some ferns like Ostrich Ferns are safe to eat, Bracken have varying concentrations of ptaquiloside, a carcinogen that is known to cause gastrointestinal cancers. Regardless, large quantities of Bracken are eaten in East Asia countries including Japan. Treating Bracken by soaking and cooking almost totally eliminates the ptaquiloside. Japan has a higher than average rate of stomach cancers. Whether this is due to Bracken in the diet or some other cause is under debate.

Young fiddleheads, harvested before much has been unfurled, are the edible parts of Bracken. One example of its use is a sweet treat called warabi-mochi, made mostly from starch extracted from fiddleheads.

Warabi-mochi has the texture of very sticky, chewy marshmallows. By itself, it is mildly sweet with an earthy flavor, but it is sometimes served with kuro mitsu (black sugar syrup) with soya flour sprinkled on top to provide extra sweetness.

Warabi-mochi has been around since at least the Heian Period (794 - 1185).

Artwork

Sakai Hōitsu (1761 -1829)

Hoitsu was a Rinpa School artist who greatly admired the works and painting style of Tawaraya Sōtatsu (1570 - 1640) and Ogata Kōrin (1658 - 1716) and did much to revive their popularity, painting his own versions of many of their works. One of the books Hoitsu published contained woodcuts of his own work, Oson Gafu, published in 1817. Bracken, Dandelion, Violet and Horsetails, below, was among them.

Utagawa Hiroshige (1797 - 1858)

Hiroshige, known for his ukiyo-e landscapes, painted many kacho-ga (birds and flowers) prints, too. His Golden Pheasant and Fern Shoots ukiyo-e was produced sometime around 1830 to 1844