Tuesday, September 20, 2022

Volcanos, Carabaos, and Misidentifications - More Botanizing in Cavite, Philippines

Carabao are these huge bovine grazers that are much cooler than cows and are a fixture of tropical Southeast Asia. 

They are used in harness to help plow the soil for farming, and their milk is for drinks and eating. When curdled the milk becomes a delicious soft white cheese called kesong putih. You can even pour the milk onto white rice, sprinkle some salt, and dig into the yummy dish (it's one of my favs).

Modern water buffalo (Da - Own work, CC BY 2.5)

One of the grasses in the Philippines is called Carabao grass (Paspalum conjugatum), due mainly to the fact Carabaos (although not cattle) seem to love this species.

Habit of A. compressus

On a second (shorter) botanizing expedition into the semi urban wilderness of the town I stayed in, I encountered a small cluster of grass that I at first thought was this species.

The dark green leaves had an interesting crinkly quality to them that reminded me of Oplismenus undulatifolius, and the specimens crawled around on robust stolons that allowed it to monopolize the shaded area under a tree.

Each hairy node produced a new ramet, along with short fibrous roots.

Stoloniferous growth in A. compressus

I typed it first as Paspalum conjugatum (carabao grass), but after some research decided that it was Axonopus compressus. The dark green leaves and penchant for shade pointed to this species, and the inflorescence nailed it.  

Attractive crinkly leaf of A. compressus

This is another species used as turf grass in the local area, but it is also used as a cover crop under oil palms, where it suppresses weeds using allelopathic chemicals (Samedani et al, 2013).. 

Inflorescence of A. compressus

Misidentifying grass species like I initially did with A. compressus above is likely not that unusual, and it seems I also did it for one of the more common and large grasses in the country

Awhile back I posted about the Destructive Duo of Imperata cylindrica and Saccharum spontaneum. The photos in that post were from the periphery of Taal Volcano in the Philippines, and I had described the taller species in them as S. spontaneum, which is called talahib here.

I had a chance to visit the area in Tagaytay last week, and I again encountered the same very tall species, along with the shorter I. cylindrica. This time I toured a national tourist attraction called the People's Park in the Sky, which dates from the dictator Marcos era and was supposed to have become a mansion at the time.

Erianthus (?) flowerheads with Taal Lake and Volcano in background

The tall grass was just as majestic as before, their flowerheads hanging high above the crowds, and the species covering a large part of the hillside. I flew my drone to take pics, and you can see me in the orange cap as I positioned the DJI Mini 2.

Red showing large masses of Erianthus (?) along hillside

The arrangement of the rather stiff leaves reminded me of Phragmites australis or Arundo donax, although the very prominent white midrib reminded me of other Saccharum spp.

Inflorescence and leaves (with white midribs) of Erianthus (?)

As always when I encounter an unknown species, I took macro photos of some dried spikelets, and I was surprised to discover that the large grasses were definitely not S. spontaneum!

Spikelets of Erianthus (?)

The dried spikelets had very long and twisted awns, which is not characteristic of awns from S. spontaneum. The awns are instead a characteristic of Erianthus contortus and E. alopecuroides, although this is likely another species entirely.

Spikelet of Erianthus (?), showing twisting awn and white hairs at base

Finally, I also came upon some specimens of what I believe is Echinochloa crus-galli. This species is commonly known here as bayokibok (Tagalog), lagtom (Bikol), marapagay (Ilokano), as well as some other common names probably.

Echinochloa crus-galli inflorescence

Like some other weedy grasses, I encountered this species as well in New Jersey, so you can tell that it is a really adaptable organism. In the Philippines, it is one of the worst weeds in rice paddies, and has become resistant to the herbicides used against it.

Echinochloa crus-galli spikelets

After 2 weeks, my time in the Philippines had come to an end, and although it was short and busy, I was gratified that I was able to spend some time botanizing in the hot and humid tropical clime. I love exploring new and interesting places, and discovering, identifying, and learning about the various species that I encounter in my travels.

Literature Cited

B. Samedani, A. S. Juraimi, M. Y. Rafii, A. R. Anuar, S. A. Sheikh Awadz, M. P. Anwar, "Allelopathic Effects of Litter Axonopus compressus against Two Weedy Species and Its Persistence in Soil", The Scientific World Journal, vol. 2013, Article ID 695404, 8 pages, 2013. https://doi.org/10.1155/2013/695404

Monday, September 12, 2022

Visiting Sugarcane's Wild Relative - Saccharum spontaneum (Talahib) in the Philippines

I first spotted the fields of Saccharum spontaneum (talahib) while travelling towards the SM Bacoor shopping mall in Bacoor, Cavite, Philippines. The grasses were in full flower, their white flowers waving languidly in the breeze, and their culms rising more than 4 meters to tower over some of the shorter urban structures around them.

Entranced by their beauty, and by the fact they were smack dab in the middle of a bustling city, I visited them again yesterday. 

In order to get a better view of at least one part of the field, I flew my DJI Mini 2 drone and took some fly-by videos. Unfortunately, the very bright sunshine made it difficult for me to see what I was shooting at, but I got at least one good video of a part of the field.

Click here for full youtube video

Along with Imperata cylindrica (kogon or cogongrass), this species forms vast grasslands all over the country, and it is hypothesized to be one of the progenitors of cultivated sugarcane, which produces most of the sugar we use today.

Unlike S. officinarum (cultivated sugarcane), S. spontaneum is widely considered to be a "weed". although various uses for parts of the plant have been developed locally. For example, it is heavily used for making various items, such as hats, brooms, baskets, walls and even furniture. In terms of its medical uses, it has been used as an astringent, emollient, refrigerant, diuretic and aphrodisiac.  

Very prominent white midrib and serrated edges

Its leaf blades are somewhat narrow (unlike S. officinarum), perhaps a cm or so in width, and it has a very prominent white midrib. The leaf margin are serrated, and you can feel the sharp edges by running your finger (carefully) down the leaf.


The Saccharum complex of species has been quite muddled and is polyphyletic. Hybridization between wild species and cultivated ones have resulted in a range of intermediate forms. In general, the cultivated S. officinarum has somewhat wider leaves and does not form extensive clonal clusters via extensive rhizomes. whereas S. spontaneum forms strong rhizomes and can thus quickly dominate an area as it spreads laterally. 

Ligule area

In order to examine the grass further, I gathered some samples of the inflorescence and took some macro shots when I got home.

The S. spontaneum spikelets come in pairs along the inflorescence branches. They do not have awns. One spikelet is pedicellate (has a stalk), while the other does not have a stalk ("sessile") and is fertile. The fertile spikelet has 2 florets, one of which is fertile. A mass of extremely long white hairs rise from the base (callus) of the spikelets. The hairs are 200-300% the length of the spikelets.

Pair of spikelets showing sessile and pedicellate spikelets

I have to admit I found the talahib fields beautiful, no matter that they were mainly composed of plants that were sometimes considered "weeds". The plumed inflorescence and towering presence of the grasses  en masse injected some beauty into the rather dirty and polluted city environment.

Single pedicellate spikelet

Tuesday, September 6, 2022

Dodging Tricycles and Jeepneys: My First Urban Botanizing in the Philippines

Jeepney in a crowded street, Cavite Province, Philippines

Heat. Humidity. Suffocation from carbon monoxide poisoning, with death or injury just an arm's length away as cars and tricycles and the ever colorful jeepneys zoom past me on narrow roads with no sidewalks.

Welcome to my first botanical expedition on the streets of Cavite Province in the Philippines.

I won't be here long, and I am otherwise busy, but I made it a point to walk the streets of the town I was in on the third day of my stay. I was excited to see what kinds of grasses thrived in this disturbed tropical urbanized area.

Of course some grasses are so successful that what I see in New Jersey (or Florida) also makes its home in this tropical location halfway around the world, and I wasn't disappointed.

In the home I am staying in, a new cluster of Imperata cylindrica (called kogon locally) has started dominating a side lawn, shading out the turf grasses and engulfing an ornamental plant. I caressed the long blade-like leaves, feeling the sharp edges and feeling almost proprietary towards this globe-trotting tropical invader. It's native to this country, but just as aggressive and dominant. In fact, it is so dominant that people here call the vast grasslands covered in this species "kogonales".

Imperata cylindrica - showing who's the boss

Once I stepped out of the home, a thriving colony of Dactyloctenium aegyptium (called damung-balang here) greeted me, their rather pretty inflorescence quite easy to identify. I have seen this same plant thriving in the heat in south Florida, and here it is a ubiquitous grass. In fact, it is one of the top weeds in vegetable and rice gardens, although it is native.

Dactyloctenium aegyptium - digitate inflorescence

The next grass I saw as I walked the suburban streets was one that at least was not in the USA. It had digitate inflorescence and strikingly enough, a row of encircling white hairs on some nodes! I typed it later as a Dichanthium spp, perhaps Dichanthium annulatum (called "lindi" here). It is naturalized in the area and probably came between 1945 and 1950s as a potential forage. Of course it escaped and is now probably found all over.

Dichanthium annulatum - inflorescence

Dichanthium annulatum - ring of white hairs around node

Dichanthium annulatum - ligule and white hairs

Dichanthium annulatum

I then entered a main road, vehicles whizzing past me close enough to feel the wind of their passing, and I encountered an individual flowering specimen that I at first thought I had last seen in the Nature Conservancy's Disney Wilderness Preserve in Florida. It had the same digitate inflorescence that seemed to curl inwards, and I was thinking it was Eustachys petraea. But looking later at lists of Philippines grasses, it is probably Chloris barbata.

Chloris barbata? - digitate inflorescence

Chloris barbata?- habit

On the sides of the main road were various stores and private residences (there does not seem to be any zoning going on obviously), and as I passed one home I noticed that a fine bladed grass had crawled up the side of a stone wall, using the cracks in the wall as its path. The specimen was stoloniferous, and had tiny spike-like inflorescence jutting out of the mass of blades at various points.

Zoysia matrella cliimbs up a wall

Zoysia matrella - the specimen had lots of spike like inflorescence

A quick inspection showed that it was a turf grass that had moseyed out of the home's lawn. I was thinking it looked slightly like Eremochloa ophiuroides (centipedegrass in the USA), another turf grass which I had profiled in an earlier post. But further study typed it as from the genus Zoysia, perhaps Zoysia matrella

This turfgrass genus is also an inhabitant of the lawns in the warmer parts of the USA, and I was not surprised to find it here as well. 

Zoysia matrella - inflorescence with purple stigmas and yellow anthers

An old "friend" made an acquaintance as I continued along the road. I encountered specimens of  Eleusine indica (called "paragis" here, as well as a LONG list of other common names due to the different dialects and languages in the country), the unmistakable inflorescence and white center a dead give-away for this ubiquitous weed. It has become naturalized in the country, and it is just as much of a pest here as in many other countries in the world.

Eleusine indica - inflorescence

Eleusine indica - white center

On the way home after ranging perhaps 0.5 km along the narrow dusty road, I stopped by a convenience store called Alfamart, and by chance happened upon a cluster of grasses that were living beneath the shade of a tired palm. The specimens were in flower, and the spikelets on the spike-like inflorescence reminded me of the sandbur (Cenchrus longispinus) that I had profiled in the USA. 

Cenchrus brownii - habit

Each spikelet had silvery white stigmas peeking out of the purple tinged spines, and in this case, I typed the species to perhaps Cenchrus brownii or Cenchrus echinatus. Both are native to the Americas but have become naturalized in the Philippines, and both are inhabitants of open waste spaces and other disturbed areas.

Cenchrus brownii - inflorescence with spikelets (and white stigmas) 

Cenchrus brownii -  inflorescence with spikelets

The spines on the spikelet function to attach to passing traffic, allowing the grass seeds to hitchhike using passersby. Unfortunately, the spines are also quite sharp and can pierce the skin (much to the horror of beachgoers everywhere with their bare feet), and I made the mistake of storing an inflorescence in my camera bag and later getting spiked when I reached into the bag! Definitely painful!  

Cenchrus seedhead attaching to unfortunate cameraman

Finally, I saw one particularly tiny grass that seemed to crop up sporadically all over, whether in decrepit lawns, or cracks in the road. This particular species had fine panicles, and I was thinking that it was the notorious Poa annua, one of the most widespread grasses in the planet and one that is even threatening the ecology in far away Antarctica!

But a closer inspection revealed some discrepancies. For one thing, the spikelets seemed much smaller than those I had typed as P. annua in the USA (on the order of only 1-2 mm long at most). Nor were the tips of the leaf blades folded and boat like, and I did not find any long ligule at the blade junctions, a diagnostic characteristic of the species. In addition, the long hairs near the ligule did not seem to be present in P. annua. I am left with a mystery, but what is life without the added incentive of such goals? I can only hope that one day I will be pointed in the right direction. Below are images of the so far unknown (but very ubiquitous here) species.

Macros of the extremely tiny spikelets (note the dark red-brown seeds in some):

I have to say that the ability of many grasses to spread and colonize far away lands was on full display during this first botanical jaunt that I did. Fully half of the species I encountered were those that I had already encountered in the USA, half a world away! Of course the count was biased by the fact I limited my tour to a semi urban environment, which usually housed cosmopolitan disturbance specialists. But I was impressed anyways. 

Urban botanizing is not for the faint of heart in this town, what with the narrow roads with no sidewalks, and the allegedly rampant holdups (especially when one is lugging around relatively expensive stuff like a DSLR camera with a large macro lens). In this first botanical expedition in the heart of a bustling town in Cavite, Philippines, I did not cover a lot of ground (perhaps 0.5 km at most away from the house), but the diversity of grasses was still a pleasant surprise. I thoroughly enjoyed it, and will do a few more before the end of my stay.