Portraits of Wildflowers

Perspectives on Nature Photography

Globose

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Texas Thistle with Spherical Flower Head 8985

Speaking of plants with globose flower heads like buttonbush and sensitive-briar, here’s yet another: Cirsium texanum, the Texas thistle. You saw an opening bud of this species in June, so I’d be remiss if I didn’t show you this follow-up picture of a follow-up stage. Note that a Texas thistle has only disk flowers; there are no ray flowers.

Today’s photograph comes from the same May 28th session as last time on Burnet Rd. near the old Merrilltown Cemetery in far north Austin.

© 2014 Steven Schwartzman

Written by Steve Schwartzman

July 17, 2014 at 6:05 AM

Another sensitive plant

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Neptunia pubescens Flower Head 9010

This column has brought you several pictures of sensitive-briars, whose compound leaves perform the neat trick of folding up within seconds after something touches them. A relative of those plants that has learned the same trick is Neptunia pubescens, called tropical neptunia, which makes its debut here today. Where the color of the sensitive-briar’s flowers varies from pink to violet, tropical neptunia wears bright yellow. Where the sensitive-briar’s tiny flowers are dispersed rather uniformly around the globes they form, a flower globe of tropical neptunia is asymmetric.

Neptunia pubescens grows in all and only the American states that border the Gulf of Mexico, as you can confirm on the USDA’s state-clickable map. Although the Texas map there doesn’t show this species in Travis County, which is where Austin is, tropical neptunia has spread widely here over the last decade and I’ve see it in various places. The one that provided today’s picture was on Burnet Rd. near the old Merrilltown Cemetery; the date was May 28.

© 2014 Steven Schwartzman

Written by Steve Schwartzman

July 16, 2014 at 5:55 AM

An endangered species, part 2

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Yesterday you heard about a May 24th field trip led by biologist Flo Oxley to look at Zizania texana, Texas wild-rice, an endangered aquatic grass that grows only in the first two miles of the San Marcos River as it emerges from Spring Lake in San Marcos, a town about 30 miles southwest of Austin.

Texas Wild-Rice 8521

The seed-bearing stalks of Texas wild-rice rise out of the water and the seed sheaths hang downward.

What I didn’t mention last time is that because of the springs that feed the river, people have lived there for over 10,000 years; in fact some scholars believe that this might well be the oldest continually inhabited site in North America. I bring that up not only because it’s interesting in its own right, but also because people continue to interact with the wild-rice in the San Marcos River, an upper portion of which is adjacent to Texas State University. It’s common in warm weather (which means most of the year in Texas) for students to sun themselves on the banks of the San Marcos, with some students and other people wending their way down the river in tubes or canoes, thus sharing the water with the wild-rice. Botanists have cordoned off some of the plants to control contact, but other plants are right out there where people are passing by. Let’s hope it remains a peaceful coexistence.

For much more information about the history of human interaction with the springs that feed the San Marcos river, you can check out these two articles:

http://www.statesman.com/news/news/local/san-marcos-spring-lake-could-warrant-world-heritag/nSxLp/

http://www.edwardsaquifer.net/sanmarcos.html

Texas Wild Rice 8638

Note: the second picture in yesterday’s post didn’t let you click to enlarge it. Now it’s gone from recalcitrant to repentant and will dutifully enlarge if you click it.

© 2014 Steven Schwartzman

Written by Steve Schwartzman

July 15, 2014 at 6:04 AM

An endangered species

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Over the three years of this blog devoted to native species I’ve never showed a picture of any that are endangered, but now you’re finally seeing one:

Texas Wild-Rice 8661

Texas wild-rice plants undulate in the flow of the San Marcos River in this downward-looking view.

On May 24th I attended a field trip led by biologist Flo Oxley to look at Zizania texana, Texas wild-rice, an aquatic grass that grows only in the first two miles of the San Marcos River as it emerges from Spring Lake in San Marcos, a town about 30 miles southwest of Austin. Flo told us that attempts to get the rice growing in other rivers in the region had failed, and even attempts farther down the San Marcos River itself haven’t succeeded. There must be just the right balance (I originally typed “rice balance”) of temperature, water flow, minerals, and other factors to make this species happy where it is and unhappy everywhere else.

Texas Wild Rice 8621

Remember that grasses are flowering plants. The little white “feathers” are actually parts of Texas wild-rice’s flowers.

 

You can read plenty more about Texas wild-rice in the following two articles:

 

http://www.tshaonline.org/handbook/online/articles/ttt01

(There’s more interest in this species now than when that article was written.)

 

http://en.wikipedia.org/wiki/Zizania_texana

 

© 2014 Steven Schwartzman

Written by Steve Schwartzman

July 14, 2014 at 5:59 AM

Mealy blue sage and truly blue sky

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Mealy Blue Sage Flowers Against Sky 2368

From the same June 13th session along Great Northern Blvd. that produced the recently shown bush sunflower pictures comes this photograph of mealy blue sage flowers, Salvia farinacea. The last Salvia you saw in these pages was the bright red cedar sage.

© 2014 Steven Schwartzman

Written by Steve Schwartzman

July 13, 2014 at 6:00 AM

A bespidered bush sunflower head

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Spider on Green Bush Sunflower Head 2516

Do you remember the bush sunflower, Simsia calva, that you saw from June 13th along Great Northern Blvd.? During that session, while photographing a still-green bush sunflower head in front of a fully open one, I noticed that the one in the foreground was serving as home to a small spider. (Did you know that spider means essentially ‘spinner’?)

© 2014 Steven Schwartzman

Written by Steve Schwartzman

July 12, 2014 at 6:00 AM

A heady sort of weirdness

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Mexican Hat with Extra Set of Rays at Tip 5401

Now that everyone’s on board with ray flowers and disk flowers in plants of the sunflower family, here’s something strange I found on June 24th at the Floral Park Dr. entrance to Great Hills Park in my neighborhood. I noticed a Mexican hat plant, Ratibida columnifera that had some normal flower heads but also had 10 heads (I counted) with an extra set of ray flowers growing helter-skelter from the tip of the column of disk flowers. That’s a place where ray flowers have no right to be, but that’s right where they were. When I asked some knowledgeable people about these unusual flower heads, one suggested a virus might be responsible and another attributed the strangeness to somatic mutation; the first could even be the cause of the second.

Some of you will remember pictures I’ve showed of the phenomenon called fasciation, so I should say that I saw no signs on this Mexican hat plant of the elongation or flattening normally associated with fasciation. No, this was a different weirdness, one I hadn’t seen before. Now you’ve seen it too.

As a postscript, let me add that on July 9th, after I’d prepared this post, about a quarter of a mile away from the location of this plant I came across a Mexican hat flower head that in addition to its normal ray flowers had a single small ray flower growing sideways from the top of its column of disk flowers.

© 2014 Steven Schwartzman

Written by Steve Schwartzman

July 11, 2014 at 5:55 AM

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