Sunday, August 14, 2022

Uncovering the lair of the sand centipede

I love my wife, but whenever I hike with her my botanizing is reduced to a minimal level.

So when I got the chance to explore a nearby trail on my own, I jumped at the opportunity and took my Nikon 3400 DSLR and  macro lens with me.

The beginning portion of the trail featured a wide sandy path, and on a previous excursion I had noticed really interesting critters that seemed to be slithering under the sand.

The trail covered with "sand centipedes"

It was the usual hot and humid Florida summer day, but this time I literally knelt to observe the little critters. The ground was really hot, but I was entranced by what I saw.

The long bodies of this grass formed sinuous patterns, the leaves half submerged in the sand and looking like the segmented legs of a centipede. I had to be careful not to keep stepping on one, although I knew that they were tough hombres that could take a few adversities and keep on ticking.

A half buried sand centipede as it crawls along the burning ground

Amazingly enough, many of them were in bloom or past bloom, and multitudes of flower and seedheads rose from the ground like the compound eyes of arthropods. They really did look like segmented critters!

Like a stomatopod with 2 eyes peering up from the sand

I identified the species as Eremochloa ophiuroides, which is a turf grass here in the southeast USA. It was introduced to the country in 1916 from China, and these specimens must have "escaped" from nearby lawns. Its common name in the area is "centipedegrass", which either refers to the overall body form or the segmented appearance of the inflorescence.

Inflorescence and stoloniferous culm that had been half buried in the sand

The species looks superficially like Stenotaphrum secundatum (which is called St. Augustine Grass here), but it is smaller and the inflorescence looks quite different.

Interestingly enough, I saw an ant going up and down the flowerheads, and I photographed what looked like aphids perched at the base of the rows of spikelets. The ant seemed to be attracted to the lumpish specks, and I was reminded of some recent research that hypothesized that  Eophiuroides might be pollinated by various insects (Joseph et al, 2020).

Ant cultivating aphids on the inflorescence?

The spikelets themselves were quite small, but the silvery stigma and purple anthers were cute, and I spent some time getting macro shots of the structures. 

Purple anthers and silvery stigmas

I must have spent an hour or more in the heat and sun examining this population of "sand centipedes". I love tiny critters, and the small size of this species was quite attractive. True, it might only be a common turfgrass to some, but the exotic location that I found them in and the fact that they were in bloom captivated the explorer in me. Beauty lies all around us, even in the most common of things.  You just need to open your mind's eye and see.

Literature Cited

V Joseph S, Harris-Shultz K, Jespersen D. Evidence of Pollinators Foraging on Centipedegrass Inflorescences. Insects. 2020 Nov 13;11(11):795. doi: 10.3390/insects11110795. PMID: 33202733; PMCID: PMC7696019.

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