Barley and Millet: Yes, Some Foods Do Grow like Weeds

Hordeum vulgare (Barley)

Barley is the 4th largest in terms of grain production, behind the other grass crops such as maize/corn, rice, and wheat. The species was domesticated around 10,000 years ago in the Eurasian region, and most barley is used for animal fodder, with the rest being used as food or for the making of fermented products such as beer. 

I was walking along one of the sidewalks here in Broomfield, CO, when I noticed quite a few attractive looking grasses along the sides of a building construction site. They weren't the usual Hordeum jubatum (commonly called foxtail barley here), which is pretty abundant in the area, and instead looked like some kinda short wheat (Triticum aestivum).

Spikelets of H. vulgare

Intrigued by the specimens, I started looking more into it. In terms of identification, I like trying to figure out the various wheat-like species only about a bit more than I like trying to make some sense of the different wheatgrass species. But after poring over identification guides and some apps, I finally decided that what I was looking at was the common barley.

Well-developed auricles of H. vulgare

Hordeum vulgare is an annual from the subfamily Pooideae, and the fact that this crop species also grows as a weed is a revelation to me. It's like coming upon a vast field of rice that grew naturally, without any help from the hand of people. Nevertheless, it turns out that this species, even though cultivated for millennia, does indeed have the capacity to still grow adventitiously along roadsides and other off-field areas.

The specimens seemed to be concentrated in that small block, as I have not really seen it elsewhere in the area, which is also intriguing. In fact, close to this cluster (the next block over) I found a second grass species that is also used as a food crop.

Panicum miliaceum (commonly called Proso Millet) is in the subfamily Panicoideae, and is just one of the many species that make up the group of food crops called "millet".

Panicum miliaceum (commonly called Proso Millet)

Proso millet was first domesticated around 8000 years ago in Northern China. There are some suggestions that this species, because of its ability to be harvested in as little as 45 days after planting, as well as its ability to produce crop in very little moisture, may have formed the bridge between hunter gatherer lifestyles and more sedentary agriculture. 

Panicum miliaceum

The domesticated crop has a tendency to revert to wild type, and the single specimen that I found was growing near a construction site, next to some landscape plantings on the sidewalk. It formed an arresting sight, with the heavy flowerheads drooping in thick bunches almost to the ground.

It is tempting to imagine how these food crops were first domesticated. Perhaps some hunter gatherers who had missed out on snagging a large prehistoric herbivore were dejectedly slouching back home, when they chanced upon fields of Panicum miliaceum, their tops overflowing with ripe grains. Or perhaps the discoverers of this new food crop were women who had been searching for edible berries and other vegetable goodies. Maybe people were getting tired of the vagaries of hunting and searching for food, and decided that planting food crops close to you might be a better idea. Or maybe a plant started as a weed infesting earlier crop plants, but was later seen to be another good food source and thus domesticated. This was what happened in the case of oats (Avena spp), which started as weeds in barley and wheat fields. The study of how agriculture started is endlessly fascinating, and one that I'll likely get into in a future post.

As an aside, the sight of food crops like these still growing wild reminds me that humanity's time here on earth is but a blip in the much larger time periods that some species inhabit. If ever our kind dies out, whether through disease or war or some unlikely event that we cannot fathom, it's likely that many of our "domesticated" plants will revert back to their wild ways, their brief tenure as indentured "servants" to the "raging apes" soon forgotten in the dim corridors of time.  

The Case for Urban Open Spaces

Bouteloua dactyloides staminate spikelet (from another location)

One of the first things I noticed here in Colorado is the prevalence of land called "Open Spaces". These Open Spaces are preserved land that is not developed, although they may be adjacent to the usual parks and other recreational locations.

According to the department that manages these areas in the city of Boulder:

The open space lands teem with native plants and wildlife and are home to threatened and endangered species. They serve as a buffer between Boulder and nearby development. They sustain agriculture uses and add untold benefits to the natural environment - clean air, water, and earth. The lands shape the urban mosaic of the Boulder Valley and provide residents with passive recreation opportunities. Trails are used by walkers, hikers, bicyclists, horseback riders, dog walkers and other passive recreational uses.

I visited one of these Open Spaces in nearby Broomfield, which has kept their city beautiful by preserving large tracts of land. In the Open Space that I visited there, walking paths crisscrossed the place, and people were jogging, walking their dogs, and generally just enjoying nature. I did some botanizing one morning, and found many native grasses, although they were outnumbered by the usual naturalized exotics that have become ubiquitous wherever humanity has taken hold.

Part of an Open Space in Broomfield, CO

I spent  an enjoyable morning just walking the paths and looking at the critters, and managed to identify some of the major species during my botanizing. As always, I am always open to corrections of my identifications.

One of the most notable denizens of the area was Bromus inermis, which existed in large clusters and is commonly called Smooth Brome. You can identify it not only by the recognizable spikelets and habit, but by a W crimp in the middle of the leaves. This species is an introduced forage grass, but it has become somewhat invasive in many places.

Bromus inermis

The native Pascopyrum smithii (called Western Wheatgrass here) was also quite abundant. It is rhizomatous, and so exists in the area in large groupings.

Pascopyrum smithii

Close to it I also saw Thinopyrum obtusiflorum, which looks somewhat similar, but is significantly taller than its neighbor. This species is not native, but had been introduced from Eurasia. It has a few common names, such as tall wheatgrass, rush wheatgrass, and Eurasian quackgrass.

Thinopyrum obtusiflorum

Another naturalized Eurasian species was also quite abundant. Agropyron cristatum is called crested wheat grass, and the sight of its flowerheads en masse was quite attractive.

Agropyron cristatum

There were also stands of what I first took to be escaped cultivated plants. but which may instead be a native called Hordeum brachyantherum (meadow barley). These were one of the taller species in the community, dwarfing everything but some of the Thinopyrum obtusiflorum specimens.

Hordeum brachyantherum

The smaller species I found along the sides of the path, and included native grasses from the genus Bouteloua (which has become one of my fav genera, and which I'll explore more in a later article).

Bouteloua gracilis (called Blue Grama grass here) was in evidence along the margins, their distinctive flowerheads dangling bright green anthers. This species is one of the dominant inhabitants of the short grass prairies in Eastern Colorado.

Bouteloua gracilis

I also found some specimens of the equally diminutive Bouteloua dactyloides (called buffalo grass here), another dominant species of the short grass prairies that has been used as turf. More on this later, but it is one of the few dioecious grasses, with some individuals having only staminate flowers,  and others only pistillate flowers.

Bouteloua dactyloides (staminate spikelet)

Other species that I found included the natives Panicum capillare, Bouteloua curtipendula, and Hordeum jubatum, as well as a few clusters of the invasive Bromus tectorum. In a creek, I even found a lone cattail (Typha sp, not Poaceae) surrounded by the invasive Phalaris arundinacea (Reed Canary Grass).

Phalaris arundinacea surrounds a lone cattail (Typha sp)

The variety of species was fantastic, and I loved the time I spent botanizing. All in all, I have to say that I am fully and heavily in support of creating such Open Spaces. I would rather see natural areas like these preserved, than more gated communities, mini-malls, McMansions and parking lots. 

As noted above, some of the advantages include:

• They serve as home to threatened and endangered species.
• They serve as a buffer between a city and nearby development.
• They sustain agriculture uses and add untold benefits to the natural environment - clean air, water, and earth.
• The lands shape the urban mosaic and provide residents with passive recreation opportunities. Trails are used by walkers, hikers, bicyclists, horseback riders, dog walkers and other passive recreational uses.

In addition, I believe Open Spaces give an airy and open vibe to a city, provide habitats for a large variety of plants and animals, and serve as a shining example of how nature and people can coexist together.

Kudos to the city of Broomfield, Boulder, and all the other enlightened communities in Colorado that have the foresight and the perseverance to protect the natural beauty of the land!

The Tragic History of the Golden Rolling Hills of California

Drone pic of golden rolling hills along Interstate 5 in California (2023). Note that the road in the photograph is NOT Interstate 5, but a side road from it.

Every time I travel to California, I always marvel at the wide open vistas of the state's iconic golden rolling hills. The trip I took last month to the Golden State was no different, and as I drove along Interstate 5 between Los Angeles and Sacramento, I could not help but compare the beautiful hilly terrain with the flat and somewhat monotonous landscapes of Florida, especially after flying my drone and gazing at the land from tens of meters up.

Ground level view of the hills from an older 2005 pic. Not the same location as drone pic above.

For many Californians, the golden hued hills are just as representative of their state as the Hollywood sign in the City of Angels, or the Golden Gate Bridge in San Francisco. But most of them probably do not know the tragic history of the creation of these scenic wonders. They do not realize that these hills were not always like that.

Instead, the hills before the arrival of Europeans in the 1700s were covered in a patchwork of perennial bunchgrasses and wildflowers. Native grasses like Elymus elymoides, Nasella (Stipa) pulchra, Hordeum jubatum, and other bunchgrasses dominated the landscape. The hills were mostly green all the way until autumn due to the preponderance of perennial plants, a far cry from the golden hue suffusing them today.

Native bunchgrass species Elymus elymoides

These perennial grasses had deep roots that allowed them to withstand drought, and they formed the basis of an ecosystem that had a diverse set of forbs and other plants that provided homes and food for the native animals in the area. They were also long-lived, with some researchers saying that some specimens may have lived for hundreds of years (Marty et al, 2005).

It was into this milieu that the Europeans arrived in the late 1700s, and brought with them (whether accidentally or not) the seeds of what would initiate a major and very rapid ecological shift in the landscape. Seeds of Eurasian grass species were introduced to the continent, along with grazing animals such as sheep and cattle. 

Avena fatua along highway

Instead of being perennials, these exotic grasses were annuals, and when they senesced they turned a golden color. Within a short timespan, they had almost completely replaced the perennials. The latter were not driven to extinction,  but were instead bracketed into increasingly smaller spots by the invading species. They could not withstand the competitive abilities of the annuals, nor the new herbivores that came along with them.

One of the most notable exotics are some oat species, Avena barbata, and Avena fatua. These 2 species have beautifully drooping inflorescence, and are cosmopolitan in distribution. 

Avena fatua with empty and ripened spikelets

From a distance they are mostly a light golden color after senescenece, their bodies coating the hillsides in countless multitudes.   

Empty glumes of Avena fatua

Avena fatua

In addition to the wild oats, other species contribute to the golden hue of the hillsides. Bromus rubens is another exotic that has become a component of the hillsides.  

Bromus rubens

Another species from the genus is called Bromus diandrus, which has beautiful spikelets and is somewhat similar looking to the dreaded cheatgrass (Bromus tectorum). But in the case of this species, the spikelets are much larger and longer.

Bromus diandrus

All the above species, as well as various Hordeum spp, are now called "naturalized exotics" because over the past several hundred years they have become an integral part of the ecosystem of California. They have become so much a part of the state that most people nowadays think they are natives, and even those who find out that they were once invaders cannot repudiate and deny the nice memories they had of driving along the roads surrounded by golden hills. 

But there are newer and more damaging species that have entered into the picture just recently. 

Hordeum (?) sp

These winter annual invasive grasses are also part of the golden hillsides, and they are rapidly conquering ground against the older naturalized exotics. One of the more notorious among them is Taeniatherum caput-medusae (medusahead grass), whose silica-rich bodies allows it to smother the competition and slowly form vast monocultures.

Taeniatherum caput-medusae (medusahead grass)

Another is Aegylops triuncialis, a relative newcomer that is also becoming a big component of the golden hued hillsides.

Aegylops triuncialis

The interesting thing is that some studies have shown that the old native perennials actually can do better against these newer invasives, unlike the naturalized exotics. But unfortunately, the tragic loss of so much of the old natural grasslands has allowed medusahead grass and its ilk to spread almost unencumbered.

Drone pic of golden rolling hills along Interstate 5 (2023)

In the end, it's still ok to marvel and gawk at the beauty of California's rolling golden hills. Change is constant in biological systems, and an irrefutable part of life. Just remember that these are the products of an invasion that started hundreds of years ago, and is still going on today.

Literature Cited

Marty, J. T., S. K. Collinge, and K. J. Rice. 2005. Responses of a remnant California native bunchgrass population to grazing, burning and climatic variation. Plant Ecology 181:101112.

Winter is Coming: How Grasses Conquered the Long Freeze

Tundra (By Education Specialist)

There are vast areas of the world where cold temperatures create problems for plants.

Such "cold stress" happens when temperatures that are below what are optimal for plants creates physiological problems for the individual plants. Depending on the species, optimal growing conditions usually hovers between 10℃ and 30℃. 

There are two types of cold stress, depending on the temperatures involved.

Chilling refers to cold stress where the temperatures range between 0℃ and 15℃, whereas freezing refers to cold stress where the temperatures are below freezing (0℃). 

In the case of freezing, plants can respond via two different methods. Freezing avoidance is when the plant is able to delay or even prevent freezing altogether in their tissues. In contrast, in freezing tolerance, the plants do not prevent ice crystal formation, but they avoid damage by controlling the size of the crystals and/or where the crystals are formed. Freeze-tolerant plants can survive even freezing of their tissues, and represent the extreme adaptation to conquering the cold over long time periods.

Deschampsia antartica (c) Lomvi2 - Wikipedia

Grasses initially evolved as tropical plants that loved the warmth. But over time, the grasses have managed to adapt to the cold and have become the most widespread vascular plant family, and present in all continents. Indeed, the grass Deschampsia antartica is only one of two vascular plants that are native to Antarctica, and its optimal growing temperature is an amazing 10℃!

Freezing can kill grasses via the formation of ice crystals. At first, ice crystals form in the extracellular spaces between cells, which causes water to be pulled from the cell interior. The loss of intracellular water (and later solutes) results in dehydration and osmotic stress. As ice crystals continue to form into the interior of the cells, the cell membranes start to degrade and programmed cell death occurs.

The evolution of the ability to tolerate freezing in the Poaceae is fascinating, and is confined mostly to species in two different subfamilies of the Poaceae. Grasses in the subfamilies Pooideae (in the Northern Hemisphere) and Danthonioideae (in the Southern Hemisphere) live in cold temperate continental regions, and they have solved the problem in two different ways. 

Hordeum jubatum of the subfamily Pooideae (Northern Hemisphere)

The grasses in subfamily Pooideae in the Northern Hemisphere all use the C3 mode of photosynthesis, and are commonly called the cool season grasses. They include many turf grasses (such as Poa pratensis or Kentucky Bluegrass), as well as food staples such as Triticum aestivum (wheat), Avena sativa (oat), and Hordeum vulgare (barley). 

The ancestors of the Pooideae evolved about 67 million years ago in small niches during the formation of the Eurasian mountain ranges. In this group, ice binding proteins evolved which decreased the rate of the formation of ice, as well as altering the shape of the ice crystals being formed. These anti-freeze proteins prevent the formation of large crystals that can physically damage cells and tissues.

Cortaderia selloana from the subfamily Danthonioideae (Southern Hemisphere)

In contrast, cold-acclimated grasses from the subfamily Danthonioideae in the Southern Hemisphere have evolved a different method for conquering the cold. The members of this group are also C3 grasses, and include the large ornamental grass Cortaderia selloana (Pampas grass). The freeze tolerant members of this subfamily produce ice-nucleation proteins that allow them to control where ice crystals form. Thus, they can prevent damage by limiting crystal formation in the extra-cellular spaces and the leaf surfaces, but not within the cell interiors.

The independent evolution of such mechanisms by the Danthonioideae and Pooideae to tolerate freezing have enabled grasses to dominate large areas where there are extreme seasonal fluctuations in temperature, and contributed to the grassy world we live in today. 

As an interesting aside, at the other end of the temperature spectrum, C4 grasses such as those in the grass subfamilies Chloridoideae and Andropogoneae - which include corn/maize (Zea mays), the bluestems (Andropogon spp), sugarcane (Saccharum officinarum), and cogon grasses (Imperata cylindrica) - have extended the range of environments conquered by the Poaceae to much warmer and drier climes. 

For a quick look at the difference between C3, C4 and CAM photosynthesis in grasses, click here.

Muhlenbergia sericea of the subfamily Chloridoideae, a C4 grass

Finally, to read more about the fascinating topic of cold adaptation in grasses in depth, check out the references below.

Note: In addition to the specialized mechanisms of freezing tolerance above, grasses can deploy other additional mechanisms for coping with the cold that are beyond the scope of this shirt post, such as accumulating fructan in their vacuoles, using supercooling (for shorter cold spells), and increasing anti-oxidant enzymes.

Phalaris arundinacea of the subfamily Pooideae

References:

Timothy J. Gallaher, T. J. Gallaher, Paul M. Peterson, P. M. Peterson, Robert J. Soreng, R. J. Soreng, Fernando O. Zuloaga, F. O. Zuloaga, De-Zhu Li, D. Li, Lynn G. Clark, L. G. Clark, Christopher D. Tyrrell, C. D. Tyrrell, Cassiano A.D. Welker, C. A.D. Welker, Elizabeth A. Kellogg, E. A. Kellogg, & Jordan K. Teisher, J. K. Teisher. (2022). Grasses through space and time: An overview of the biogeographical and macroevolutionary history of Poaceae. Journal of systematics and evolution, 60, 522-569. doi: 10.1111/jse.12857

Schubert M, Humphreys AM, Lindberg CL, Preston JC, Fjellheim S. 2020. To coldly go where no grass has gone before: A multidisciplinary review of cold adaptation in Poaceae. In: Annual Plant Reviews online.Wiley.523–562.

Hordeum jubatum (foxtail barley grass) in Baanf National Park

In 2008, I visited Baanf National Park and Jasper National Park in Canada.

In addition to the absolutely beautiful scenery (I highly recommend the place to visit), the area had lots of interesting grasses for us Orang Poa (grass people).

One of the interesting grasses I saw was during a trip to Lake Louise, when I noticed a purplish flowered "weeds" hugging the sides of the main path around the lake.

Hugging the path

 I looked more closely and was delighted to see that the grass had really beautiful inflorescences coming out of its somewhat bedraggled blades.

Lots of seedheads

I later identified the species as Hordeum jubatum, which is called foxtail barley grass by the locals. It is an ornamental grass in some areas due to its feathery fox-like seedheads, but it can also be quite dangerous to pets and the like because the awned seeds can attach and burrow into sensitive areas of dogs like their noses and ears, so deeply sometimes that surgery is needed to remove them.

But a more interesting tidbit is that this same grass was mentioned in this area more than a hundred years ago, in a gardening journal:

A striking feature of the national park landscape is the squirrel or fox-tailed grass, Hordeum jubatum. Clumps of it are found almost anywhere, but sometimes it takes posession of considerable areas of level ground, and, waving in the win on a sunshiny morning, is one of the most beautiful pictures imaginable.

- Gardening, vol 6, 1898 (Sept 15, 1897 - Sept 1, 1898)

I found it fascinating that the same grass that interested me today also enchanted visitors to the park more than a century ago!