Monday, August 31, 2020

Weed of the Month: Echinochloa crus-galli (barnyard grass)

Echinochloa crus-galli (barnyard grass) spikelets with purple stigma

Echinochloa crus-galli is commonly known as cockspur (or cockspur grass), barnyard millet, Japanese millet, water grass, common barnyard grass, or simply "barnyard grass".

Echinochloa crus-galli (barnyard grass) with yellowish anthers

This species is considered one of the world's worst weeds, because it reduces crop yields and causes forage crops to fail by removing up to 80% of the available soil nitrogen.

Echinochloa crus-galli (barnyard grass), no ligules

It is an invasive weed in all the states in the continental USA, and is particularly adapted to wet areas such as paddy fields

I found it growing from the side of a stand of Imperata cylindrica (Japanese Blood Grass).

Specimen of this cosmopolitan grass from the Philippines

I identified it from the absent ligule and the distinctive inflorescence, including the fact all the spikelets were crowded on only one side of the central axis.

Echinochloa crus-galli (barnyard grass), with purplish base

Sunday, August 30, 2020

When an ornamental goes bad!

Chasmanthium latifolium
Pretty spikelets of Chasmanthium latifolium

Most ornamental grasses behave themselves. They do what they're supposed to do. They sit where they've been placed and look pretty for all the guests.

But there are a few ornamentals that don't stick to the rules. They waylay unsuspecting gardeners with their beauty, but once they've gotten safely tucked into the soil, they slowly show their true colors.

At first there are just a few new culms coming out, their appearance causing the gardener to exclaim in delight. But soon there are more than just a few of these sprouts, and before long the new grass is starting to take over the land, crowding out other plants.

Chasmanthium latifolium
Rhizome and roots of Chasmanthium latifolium

Chasmanthium latifolium is known by many common names, including woodoats, inland sea oats, northern sea oats, and river oats. It has attractive light green foliage and unique hanging inflorescence that vibrate in the slightest breeze. 

It is also a rhizomatous species that is a prolific seed producer, and the unwary owner soon finds his garden starting to be overrun by this ornamental grass. In the case of the image below, a few transplants spread throughout the path and sides of the path, growing between the stepping stones.

Chasmanthium latifolium
Chasmanthium latifolium taking over garden

It has even started crowding out any nearby plants, the beautiful flowerheads rising above the surrounding vegetation like some conquering army proclaiming victory over its competitors. In the case of the unfortunate iris below (in the foreground, with larger broader  leaves), C. latifolium has enveloped it from the back with masses of smaller leaves.

Chasmanthium latifolium crowding out Iris from behind

In the end it is up to the owner to make sure that the pretty ornamental that he or she plants will not suddenly become too aggressive and uncontrolled in the garden. Grasses that have rhizomes and are prolific seed producers need to be used with care. Do your homework, and always remember that these grasses are living things, and that they do not exist for you but for their own ultimately selfish reasons.

Thursday, August 27, 2020

An Empire of Grass


The grasses are by far the most important family of plants, whether in terms of their economic value, or in terms of ecology. Although the vast natural tallgrass prairies that used to cloak more than 67 million ha of the country are long gone, they have been mainly replaced by other types of grassland, whether corn, or wheat, or some other species in the Poaceae.

The USA has about 1 billion ha of land, and I was curious about how much of that land is currently dominated by grasses, so I combed the records, added up all the figures, and created a graph. 

As you can see from the figure above, about 37% of the entire land area of the USA is dominated by grasses. This includes all the natural prairies, rangeland, and pastures. It also includes all agricultural land devoted to grass crops such as rice, wheat, corn, millet, and other grasses. Finally, it also includes that most hated of "grassland", the suburban lawn.

Grasses that are part of the natural landscape, and those that are used as rangeland and pastures make up the majority of the land dominated by grasses (272 million ha), with agricultural areas coming in second (58.5 million ha). Huge amounts of suburbia are also made up of manicured lawns (16 million ha), which suck up water at a prodigious rate, and are so despised by some that anti-lawn movements have actually sprung up. 

Sum them all up and you get an amazing number, and no other plant family comes close to the area devoted to grasses in the country. In that sense, the USA really is an Empire of Grass.



Milesi C, Running SW, Elvidge CD, Dietz JB, Tuttle BT, Nemani RR (2005) Mapping and modeling the biogeochemical cycling of turf grasses in the United States. Environmental Management 36: 426-438

USDA Charts and Maps

Monday, August 24, 2020

Roadside Ecology (Or why there are lines of grasses along roadsides in desert environs)


I've always wondered when driving through desert areas why you sometimes see long continuous lines of grasses along both sides of the road. This thin strip of vegetation that presses close against the hard asphalt or concrete seems almost artificial.

A discussion on this topic once came up on a group thread, and various possibilities were mentioned. Water runoff was one possibility, since the non-porous road surface might concentrate water along the sides, thus providing much needed moisture to the plants. One other possibility is that some chemical runoff from the road itself or from the vehicles using the road provide some nutrient(s) that support the growth of the grasses. Indeed, one study found that nitrogen and phosphorus from vehicle exhaust enhanced the growth of surrounding vegetation (Angold 1997). Finally, the sides of roads may also have some kind of micro-climate that is conducive to colonization by grasses.

There are probably other possibilities, but whatever the real reason, I have to admit that I almost always admire the cool long lines of grasses as I zip along the highways and byways of the more arid areas in the West Coast, USA.

Literature Cited:

Angold, P.G., 1997. The impact of a road upon adjacent heathland vegetation: effects on plant species composition. Journal of Applied Ecology 34, 409–417.

Sunday, August 23, 2020

A stiltgrass-free area in the northeast USA? Surely you jest! Exploring the boundary of Microstegium vimineum


Pristine forest understory sans Microstegium vimineum

The invasive grass Microstegium vimineum (Stiltgrass) is so ubiquitous in New Jersey forested areas that it would be hard to imagine a time when it wasn't the noxious weed that it is right now.

In fact, its spread from Tennessee in 1919 was well documented, with the species reaching Virginia in 1931, North Carolina in 1933, and Alabama in 1934. From there it spread to Pennsylvania and Kentucky in 1938, Delaware in 1942, and finally New Jersey in 1959. But even in the early 1980s, it was still fairly uncommon in NJ (Hunt et al, 1992). 

Surveyed areas (A) Stockbridge, MA parks, and (B) Storm King State Park, NY

There are still states in the Northeast where M. vimineum has not been documented, or is only known from a few samples, and a quick look at the map of the species at EDDMaps shows the approximate boundaries of its distribution.

In order to confirm the presence or absence of this invasive species, I hiked an area at the boundary of its main invasion front (icon A in image above, in Massachusetts), as well as a spot some distance to the south (icon B, in New York State). M. vimineum was first discovered at 3 sites in NY in the early 1990s, and appeared in Hamden County, Massachusetts in 1998, so the species is a fairly recent arrival to at least the latter state.

Surveyed areas in Massachussetts

In Massachusetts, I hiked several state and public parks, including:

  • Mount Greylock State Reservation
  • Alford Springs Trail 
  • Monument Mountain 
  • Benedict Pond Loop and Appalachian Trail in Beartown State Forest
  • Basin Pond Loop and Appalachian Trail in October Mountain State Forest
In none of these hikes in MA did I see a single specimen of M. vimineum, although there were quite a few look-alikes. I even surveyed a short 100 meter portion of the Appalachian Trail in October Mountain State Forest near Becket Rd, where the species was reportedly spotted in 2013, as in here. But again, I failed to find evidence of stiltgrass, which made me wonder whether previous sightings of the species in the area had been mis-identifications of some other plant, such as Leersia virginica.

Stiltgrass look-alikes

What I found instead was a quite diverse understory, with beautiful ferns dominating the shadier undisturbed areas, and many different kinds of other herbaceous plants sharing the limelight! It was quite a refreshing change from the carpets of M.vimineum that sometimes even lines the sides of paths in NJ.

It was a different story across the border in NY state, where I found ample evidence of the species in Storm King State Park. In fact, the small parking lot next to the trailhead had a dense carpet of stiltgrass sprawling under the tree canopy, as well as on decorative depressions in the parking lot wall.

M. vimineum near trailhead parking lot of Storm King State Park, NY

Farther out in the trail itself, there were occasional clumps of the species along the sides, but nowhere near the level of infestation as in some NJ parks. Nevertheless, I saw ferns surrounded by stiltgrass, their fronds rising desperately out of the grass like the arms of a drowning swimmer.

Ferns surrounded by Stiltgrass.

I'll admit that the sight of the invasive species generated some excitement in me, given that I had not seen it at all in the next door state. This feeling was however tempered by the knowledge that it is probably only a matter of time before that surveyed area in MA is also inundated with stiltgrass, perhaps through seeds carried along the Appalachian Trail. Studies have shown that without human or other intervention, that M. vimineum actually spreads quite slowly (Rauschert, 2010), but its advance has so far been steady and inexorable.

Appalachian Trail near Beckett Road in October Mountain State Forest, MA

Literature Cited

EDDMapS. 2020. Early Detection & Distribution Mapping System. The University of Georgia - Center for Invasive Species and Ecosystem Health. Available online at; last accessed August 21, 2020.

Hunt, David M.; Zaremba, Robert E. 1992. The northeastward spread of Microstegium vimineum (Poaceae) into New York and adjacent states. Rhodora. 94(878): 167-170.

Rauschert, E.S.J. 2010. Slow spread of the aggressive invader, Microstegium vimineum (Japanese stiltgrass). Biological Invasions12:563-579

Sunday, August 16, 2020

Looking at things in a different way: Pennisetum setaceum and Panicum virgatum spikelets

I wanted to show how beautiful grass flowers can be, so I took a few macro shots of the spikelets of the warm season grasses Pennisetum setaceum and Panicum virgatum

Panicum virgatum 

In the images you can clearly see the fuzzy looking stigma, as well as the yellow anthers in the case of the Pennisetum.

In the movie Dead Poets Society, Robin Williams tells his students that We must constantly look at things in a different way.

Pennisetum setaceum

So the next time someone tells you grasses don't have flowers or are too plain, just tell them that all they have to do is to look at the world (and grasses) in a different way, because beauty sometimes hides in surprising places.

Panicum virgatum

Friday, August 14, 2020

Native grasses during a hike at the Environmental Education Center at Lord Stirling Park (Great Swamp National Wildlife Refuge)

Inflorescence of Andropogon gerardii

Little did I know when we started our hike at the Environmental Education Center (EEC) at Lord Stirling Park that I would finally encounter and identify one of my more sought after species, one of the members of the legendary "Four Horsemen" of the Tall Grass Prairies. These 4 native grasses (Andropogon gerardii/Big Bluestem, Panicum virgatum/Swirchgrass, Sorghatrum nutans/Indiangrass, and Schizachyrium scoparium/Little Bluestem) dominated vast swathes of America before giving way to the spread of another type of grassland with the introduction of corn. 

I was not expecting much because the EEC is located in the Great Swamp National Wildlife Refuge, a remnant of the Wisconsin Glacier, which retreated around 11,000 years ago to form the New Jersey Wetlands. So I thought I would see lots of marshy areas, wilt under the high humidity, and of course be attacked by lots of mosquitoes.

What I did not expect was a very well maintained, and honestly impressive trail system, but that's what I saw. A significant proportion of the path was on wooden boardwalks, which was impressive, and the trails were wide enough that you didn't have to touch vegetation on either side - always a recipe for picking up ticks. It even had a garden near the EEC building, with labeled plants, though not many of the plants were flowering at the time we went there.

Carpet of Microstegium vimineum

We found a trail map of the area and decided that we would move from trail to trail along the periphery of the place, thus maximizing our hiking time. We first traveled counter clockwise along the yellow trail towards Lenape Meadow, and as usual I saw lots of Microstegium vimineum (Stiltgrass) covering the sides of the path, as well as sometimes extending deeper into canopy. This invasive grass is the bane of forest managers, and I had already grown used to encountering it every time I entered some forested area. You can identify stilt grass by the bamboo-like leaves as well as the silvery stripe that runs along the upper leaf surface.

Close up of leaves of Microstegium vimineum

Fortunately however, we did encounter some other plants along the way, including a quite striking plant with dark red flowers, which I later identified as Lobelia cardinalis.

Lobelia cardinalis

We also saw lots of cattails (Typha species) as we crossed the Boondocks Boardwalk along the north end of Lord Stirling Park. The sight of so many cattails was interesting and unexpected because this plant is being pushed aside by a grass called Phragmites australis in most places.. The reason for its health in the area seems to be because the park managers are actively controlling populations of the invasive grass.


But what excited me at first was the sight of clumps of S. scoparium (Little Bluestem) at Lenape Meadow.

A clump of S. scoparium at Lenape Meadow (center of pic)

I've always been fond of this species ever since I saw fields of it in New Hampshire, with the distinctive red flowerheads arrowing stright up into the air. Of course, it's only early August, so the S. scoparium I saw at Lenape Meadow still had not gained their full beauty.

S. scoparium in New Hampshire

However, my delight at the discovery of my old friend Little Bluestem was nothing to the amazement that I experienced when we passed Alexander Meadow at the extreme southwest of the park. There I saw a field of grass that almost made my jaw drop. Rising more than 3 meters into the air were flowerheads that looked like turkey feet waving in the air. I had come upon my first field of A. gerardii (Big Bluestem)!!!!

I believe I have never encountered this species before, ever since I started learning more about grasses last year.  The distinctive turkey feet flowerheads and towering height made them almost instantly recognizable, and we passed through the meadow surrounded by these impressive grasses.

A. gerardii inflorescence, looking like turkey feet

I took a few macroshots of the spikelets, which were tightly appressed and had a few dangling yellow or red anthers, although it was obvious that full anthesis had not yet started for many flowerheads.

I also saw quite a number of P. virgatum (Switchgrass) in the field, their wispy flowerheads forming almost a mist-like cloud above the grasses. This species is the 3rd member of the Four Horsemen of the Tall Grass Prairie present in the park, and I had a feeling the 4th and final member (Sorghastrum nutans) might also be somewhere there, although I did not have time to explore the place further.

P.virgatum flowerheads

In the end, it was a very nice and productive hike, although we did sweat throughout the experience, and were bitten by quite a few mosquitoes. 

Sunday, August 2, 2020

Sentinels to McNeill's Last Charge

More than 150 years ago, a small group of Confederate soldiers led by Capt. John Hanson McNeill charged against a hundred man detachment of American soldiers near a bridge in Mt. Jackson, VA. Most of the Confederates were captured, and their leader was mortally wounded.

A plaque honoring that battle was erected in 1999 (38°43'44.2"N 78°38'41.4"W), and today farmland surrounds the area.

I stopped by that plaque in order to examine the large tall grasses that crowded close to it, on the periphery of cultivated fields.

The grasses were nearly 2 meters tall, with purple panicles, very large white midribs on their blades, and membranous hairy ligules.  I tentatively identified them as Sorghum halepense.

S. halepense is also called Johnsongrass here in the USA, after one of  the men who helped spread the species as a forage crop in the 1830s and 1840s.

Like quite a few plants that were somewhat thoughtlessly introduced to the country during that early era, the grass soon became a major weed, especially of agricultural land.

When I was driving down the local highways between Mt. Clifton and New Market in Virginia, stands of this grass were quite evident along the roadsides that passed through cultivated areas, their erect forms standing tall like sentinels in front of expansive cornfields.

Saturday, August 1, 2020

Deschampsia flexuosa (Crinkled Hairgrass) in Shenandoah National Park

During hikes at Shenandoah National Park in mid-July, one of the more notable grasses I saw was a somewhat short species with very airy panicles. Some had only a few flower spikes, but a few looked fantastic, as if a cloud of midges was hovering above them, and I have to admit I spent time during hikes paying attention to specimens of this species that I saw by the side of the trail.

The spikelets themselves were also quite notable, with 2 sinuous awns forking out from the 2 florets that made up each spikelet. But they were very tiny, and I must have been a sight kneeling by the side of the path trying to take macro pics of it!

I later identified the species as Deschampsia flexuosa with the help of Zihao Wang from a grass identification group in facebook.

If you ever hike Shenandoah National Park, then keep your eyes open for this very pretty little grass as you make your way along one of the many gorgeous trails of this national park.