PLANTS HAVE ODD TRAITS
by Whit Gibbons
May 20, 2007
If plants gave out honors among themselves, one awards category might
be "strangers in a strange land: surviving against the odds."
Among the prime candidates for such an honor would be ginkgoes, Franklinia,
The "tumbling tumbleweed" looked good in old Hollywood Westerns
as a round, basket-like object rolling across the trail in front of a
posse or a cowpoke on a dark and windy day. Tumbleweed is part of the
legends of the Old West. But tumbleweed qualifies as a glamour species
only in the eyes of moviegoers from back east. The species was never popular
with ranchers and farmers. The leaves are sharp, and people and horses
alike can suffer painful cuts from the spines. In the modern-day West,
tumbleweed-vehicle collisions can result in the need for a new paint job.
The huge, dried balls of plants add to their nuisance value by piling
up against houses, barns, and fences, creating a fire hazard if nothing
else. The fire specter is dramatically increased by the prospect of a
tumbling fireball leaving a trail of burning prairie grasses or crops.
Farmers in the Dakotas in the late 1800s were the first to recognize tumbleweed
as a serious pest. None of them liked it one bit. Tumbleweed was so destructive
to the American frontier that some farmers even hinted at conspiracy.
As an identifiable social and religious group with different customs,
Russian Mennonites were already a target for frontier discrimination.
As tumbleweed problems increased, some farmers blamed the Mennonites.
The religious group was accused of intentionally introducing the noxious
weed to America in a vindictive plot to get even for the prejudices against
them. The U.S. Secretary of Agriculture sent a botanist to the region
to study the tumbleweed problem and seek control measures. He eventually
demonstrated that the plant, known by botanists as Russian thistle and
by some people as wind witch, was introduced by accident in a shipment
of flax seeds from Europe, where the plant was not native either. The
finding dismissed the claims against the Mennonites.
The community of the Great Plains first felt the brunt of the newly introduced
agricultural pest as the rolling plants spread their seeds across the
land, invading croplands, towns, and open prairie. Ironically, although
a bane to developing farmlands, tumbleweed owes its success to agricultural
practices. A tumbleweed plant disperses its seeds by rolling across the
landscape. The clearing of forests and the elimination of tall prairie
grasses aided such a lifestyle; the dense natural habitats would not have
allowed suitable dispersal or seedling establishment. The worldwide prosperity
of Russian thistle can be attributed to an agricultural society that set
up ideal conditions for its survival.
Tumbleweed is a botanical success story in barren habitats throughout
much of the world, including Eurasia, Australia, and North America. According
to some accounts, despite its abundance in some areas of the world, tumbleweed
is apparently extinct in its original native habitat in Russia.
Franklinia, a member of the tea family, is a small evergreen tree originally
described in the 1700s by William Bartram. The early explorer discovered
a grove of two to three acres in the bottomland forests along the Altamaha
River in Georgia. Neither the grove nor a single tree has ever been rediscovered.
The only survivors of the entire species, available from horticultural
companies, are descendants from seeds Bartram collected and sent to England.
Ginkgo trees are also extinct in the wild and no one knows for sure where
they came from. Only one species exists, with a botanical history that
traces it back to temple gardens of China. The ginkgo has one of the longest
fossil records among the higher plants, has no wild representatives, and
yet prospers today in the Orient and North America. Most are within planting
distance of a house or building.
Franklinia, ginkgoes, and tumbleweed are botanical paradoxes. In contrast
to the many species threatened today by encounters with humans, all these
species owe their existence in America, and perhaps anywhere, to a consequence
of the intermix of their natural history and a timely involvement by humans.
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