Sunday, January 13, 2019

Botanical Travel: Where the Weeds Are Strange

lantana, Lantana camara
lantana (Lantana camara)
Growing on the roadsides and vacant lots in Costa Rica, we saw lantana (Lantana camara, vervain family, Verbenaceae). In Hawaii it was Kahili ginger (Hedychium gardnerianum, ginger family Zingiberaceae)
Kahili ginger
Kahili ginger
Here is Kahili ginger, the dark green leaves, filling the forest understory in Hawaii
Kahili ginger in forest
All the dark green leaves are Kahili ginger
Wow! Aren't those pretty! But weird weeds to a Coloradan.

Along sidewalks in the tropics, I've seen all these pretty little flowers

tropical weed
a composite (sunflower family), but which one?
tropical weeds
tropical weeds
A nice white-flowered composite, attracting butterflies
Clearly these were weeds but they were also quite attractive. And plants were unknown to me; I can at most identify them to plant family. (Of course there are less striking weeds as well, grasses for example.)

Weed is a human concept, a plant in the wrong place, so the most beautiful flower in the world is a weed if you don't want it.

But, like all plants, weeds are subject to climate limitations. They can grow in some conditions but not in others.

One important factor in climate is cold. Winter is a critical divider of the plant world. Some plants can survive a hard frost but most cannot. Conversely, in the tropics where there are no hard frosts, the ability to withstand frost is of no use, like an overcoat in a Florida closet. Different characteristics are important and different plants invade tropical lawns and roadsides and aggravate farmers and gardeners.

The more climate differs between two places, the fewer plants can grow in both, leading to quite different sets of weeds. There are lots of differences in climate between Colorado and New York and tropical places like Costa Rica and Hawaii. And therefore the conspicuous weeds are different.

What is this?
tropical weed

Or this?

tropical weed

I can work out names, if the identification books for the region are good, but they aren't the weeds I live with and so I don't immediately know their names.

J.R.R. Tolkien wrote, "in far Harad, where the stars are strange," and I have always held unfamiliar constellations as evoking distant, exotic places.

But I would also say, "where the weeds are strange."  Weeds are so familiar--ignored but familiar--so that a place with ones you don't recognize must be far from home.

When you are traveling, notice and enjoy the strangeness.

Comments and corrections welcome.

Note: "composite" is a term for plants in the sunflower family, Asteraceae because the "flower" is a actually a group very small flowers, packed together.

Kathy Keeler, A Wandering Botanist


  1. Last pic is of Biophytum sensitivum a plant native to India and Asia.

    1. Certainly could be. I should have taken a better picture. Thank you.

  2. Is it Bidens pilosa(white flower).

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