Friday, October 23, 2020

Why does maize (corn) feature so much in people's nightmares?

A nightmarish visage

They stand like dark sentinels, their leathery surfaces wrinkled and tough, the corn cobs peering out from behind thick leaves like grotesque mutants. It's almost Halloween, and as expected I see a lot of gardening stores and Farmer's Markets selling dried maize plants. 

If you've never seen such merchandize, then let me assure you they sometimes really do look creepy, and quite a fitting decoration for a tradition that was once a Celtic celebration to ward off ghosts.

Halloween sentinels

But why does corn feature so prominently in horror stories and movies, and in the nightmares of people? Witness for example, Stephen King's classic story "Children of the Corn", or movies like "Husk" and "Night of the Scarecrow." Is there something about this species that inspires such fear and sometimes revulsion?

I think it has to do more with cornfields, than the actual plant itself. There is just something slightly frightening about seeing endless rows of identical maize plants. They rise above you when you walk into them, enclosing you in a moist claustrophobic environment where your imagination can be pushed into thinking about some unpleasant possibilities.

Could you get lost in such a maze, perhaps fated to wander forever within its green bosom? And what are those sinister sounds that you hear, the faint susurrations, the whispers of the corn as the wind caresses their ripe and decaying bodies? What slavering monsters, both human and unhuman, lurk behind the next towering stalk?

Sunday, October 18, 2020

A row of Pennisetum!


Image: Courtesy of 刘伟

I am not especially enamored of Pennisetum, but no one can deny that the flowerheads of these grasses are usually very pretty, which makes it a favorite ornamental.

Here 刘伟 lines up quite a few samples for our delectation (from left to right):

Pennisetum macrourum, P. setaceum 'rubrum', P. setaceum ‘Rueppelii’, P. orientale 'Tall', P. alopecuroides 'Purple', P. alopecuroides ‘Viridescens’, P. alopecuroides 'Hamelin'

Beauty in an arid and darkening landscape: Oryzopsis hymenoides in New Mexico

During our trip to New Mexico in Fall 2019, we visited White Sands National Monument, and one of the notable species we noticed among the few other plants that dotted the stark landscape was Oryzopsis hymenoides (synonym Achnatherum hymenoides), whose common names include Indian ricegrass and sand rice grass.

While traveling later after a visit to Bandelier National Monument, we stopped to view some scenery at a small hilltop. While the wife went off to find a nice viewpoint, I wandered around in wonder at the dried whitish grasses that stood like ancient sentinels on top of the small hill.

One grass in particular looked fantastic in the light of dusk, and with the help of L. Pilkington in a grass identification group, I determined that it was indeed my old friend from White Sands.

This C3 perennial bunchgrass is a native to the area, and can survive in quite a range of environments, from desert to pine forests. In other words, it is like many other grasses in its inherent adaptability, although it does particularly well in sandy soil, using it roots to anchor the particles together. 

I'd also like to suggest that it would make a great ornamental, at least in its dried state, and in the dusk ;-)

Tuesday, October 13, 2020

White flowerheads in a white landscape: Chloris virgata in White Sands National Monument


In Fall of 2019 I visited the White Sands National Monument in New Mexico to view some of the tenacious grasses that thrived in this relatively inhospitable environment.

While dropping by the visitor center of that park I was met by a wonderful sight. All by its lonesome on one of the pebble strewn islands that marked the boundary of the center was a single plant. It stood straight and tall, the white flowerheads above it gently waving in the breeze. 

It was not an ornamental, planted by some gardener, but a wayward seed that had sprouted and grown into a mature plant, struggling past the pebbles and flourishing in the light.  

I found the pictures of this grass again recently, and managed to tentatively identify it as Chloris virgata, a widespread species that nevertheless was not present in New Jersey. It has many common names, such as feather fingergrass and feather windmillgrass.

It is an annual grass that is worldwide in distribution and because of its hardy nature can oftentimes be found in disturbed areas as well, such as roadsides.

I must admit, I knew none of this information when I first spotted it that fine day in New Mexico. All I knew was how amazing it was to find such a beautiful plant growing tall and firm and proud in that isolated visitor center.

Sunday, October 11, 2020

My houseplant is a grass!

Some people decorate their homes with orchids, and many go with the old standbys, tough aroids like Philodendrons. 

Winter is coming, and now I have a new houseplant.

It started as one culm, a single leaf blade coming out of the ground. But fairly soon the tiny pot that it called home was filled with red-green leaves.

Meet my new houseplant. Japanese Blood Grass. Cogon Grass. Imperata cylindrica.

How weird is that? ;-)

Saturday, October 3, 2020

Meet the strange shimmering spikelets of Schizachyrium scoparium (Little Bluestem)

When an observer looks at the seedheads of Schizachyrium scoparium (Little Bluestem), they may gasp at its beauty, and marvel at the whitish fluff that decorate the reddish main axis of the inflorescence. But little do they know what a complex piece of biological engineering that whitish fluff is when viewed at the macro level. 

As many of the Orang Poa (Grass People) know, the unit of reproduction in grasses is the spikelet. The spikelet contains the florets ("flowers") of the grass, and of course the florets (like any flower) contain the stamens (male) and pistils (female). 

In the case of S. scoparium, the spikelets form a complex little unit with many parts. 

Pairs of spikelets run along the axis of the raceme of the inflorescence. Each pair is composed of 2 spikelets (see image below).

The smaller spikelet in the pair sits on top of a pedicel, and is rudimentary and hairy. The larger and fertile spikelet is sessile, with two structures called glumes completely covering the two florets inside. One of the florets is sterile, while the fertile floret has a long bent awn that extends from its central nerve and extends out of the glumes.  You can see the bent awn of the fertile floret in the image below, but the rest of the floret is hidden inside the enclosing glumes.

The unit of dispersal is composed of the two spikelets, in addition to a short segment of the raceme axis. An abscission layer below the axis segment allows the seed-carrying unit to disarticulate from the raceme, and the hairs on the rudimentary spikelet and the axis segment allow it to be carried by the wind for very short distances (typically less than 2 meters from the mother plant).

As I watched, one of the "seeds" floated onto the ground and I took pics of it before the wind could blow it away (see image above). 

(B) is the bent awn of the fertile floret that is being hidden between the enclosing glumes, and (A) is the rudimentary spikelet which sits on a pedicel. The axis segment that connected the unit to the next spikelet pair is labeled (C), and you can see at the top where it was detached from the raceme.

So the next time you see seedheads of S. scoparium, just remember how such simple looking structures actually are composed of wonderfully intricate parts! 


Thursday, October 1, 2020

Is Distichlis spicata (Saltgrass) precocious at Cheesequake State Park?

Distichlis spicata (Saltgrass)

During my last trip to Cheesequake State Park, I noticed that in the area closest to the entrance of the walkway to the Crabbing Bridge, there were quite a lot of dried up small seedheads poking out from the grass.

Not knowing what they were I used my macro to take a few photos of the seedheads (amazingly enough, the macro could focus on faraway and smaller items).

Distichlis spicata (Saltgrass)

When I got home, I was delighted to find out that the grass was another of the common species inhabiting salt marshes. Distichlis spicata is a small-sized perennial that is extremely salt tolerant, and can expand via both stolons and rhizomes. It tends to be found in the high marsh, and the interesting thing about the species is that it is dioecious, with male and female flowers residing on separate plants.

Although such an arrangement is common in animals, in sessile plants this might mean that population growth in the species is slower because the plants cannot self-pollinate. There is also 50% less pollen in the population, and the direction of travel of pollen makes a difference. If pollen goes from one male plant to another male, then it is wasted, although this can be somewhat negated by using vectors such as insect pollinators that can be pushed in one direction.

Distichlis spicata (Saltgrass)

Nevertheless, many species of plants are dioecious, so the mechanisms by which they compete against monoecious plants have been investigated.

Some studies have suggested that long lived perennials achieve this by the dioecious female producing many more seeds than their competitors. Another possible mechanism is to flower earlier during the lifecycle, so that the population size grows incrementally faster, and some papers have seen this happen as well.

As a wind-pollinated grass with no insect pollinators, one has to wonder whether D. spicata uses one mechanism or the other (or maybe both), but some studies show this species has low seed production. So the question is whether D. spicata flowers earlier in its development, or whether its ability to spread and dominate an area comes through some third option. Perhaps vegetative reproduction through rhizomes is the secret weapon that it uses to overcome the dioecious dilemma.

There's so much we don't know about our fellow inhabitants on Earth!