Lasiacis procerrima – The Wooly Tuft

Back in June, when the Stigmaphyllon was in bloom in a newly disturbed area, I noticed another plant growing right along with the vine:

It had what I thought was a “grassy” kind of flower:

Later I noticed it along the path where I walk with the dogs in the planted pine forest.

It has soft, velvety leaves and it blooms like a grass. Could it be a grass with those wide leaves?

The answer is yes.
Once I stopped to think about it, corn is a grass (illustration from wikipedia):

Bamboo is a grass. Sugar cane is a grass.

So, maybe this plant growing here in disturbed areas is also a grass.

I put an image of it up on Flickr and got a suggested ID almost immediately from Tony from Sidney: Lasiacis procerrima. Although another Lasciasis species, L. oaxacensis, has been identified in Panama, and although six Lasciasis species are listed for Monteverde in Costa Rica, I’m leaning toward Tony’s identification for the following reason:

“Lasiacis procerrima is the most distinctive species in the genus and is rarely misidentified. The very large leaves with prominent, clasping, basal lobes and the large diffuse panicles readily distinguishes it from all other American panicoid species.” (Annals of the Missouri Botanical Garden)

Yes, Lasiacis is a Grass

Although there is no specific entry in wikipedia for Lasiacis, the genus is listed as belonging to the family Poaceae, the grass family. The prefix Lasi- in Latin means “wooly,” which describes the tuft at the tip of the floret (small flower), and akis is Greek for point, which refers to that tip. (Delta Intkey) I have been unable to find any information on procerrima or oaxacensis, the Panamanian species, although cera means “waxy” and the suffix -ceras means “horn.” Oaxa- may refer to Oaxaca, Mexico.

So, What is a Grass?

Grasses are monocots, a group that includes orchids, gingers, bananas, and many other economically important plants. The grass family is Poaceae. Poa is the ancient Greek name for a grass used as fodder. (Dave’s botanary)

Grass is a flowering plant, and the family is one of the largest, in fact: 500 genera, 8,000 species. Stems are round and usually hollow (remember the rhyme: “grasses are hollow right down to the ground.”). Leaves are alternate. At the base of the leaf, where it is attached to the stem, the leaf surface overlaps the stem. The blade itself has parallel veins and is strap-shaped. (zipcodezoo)

Here are some of those features in Lasiacis:

And, yes, the stem is hollow.

Grasses have Flowers…

The basic unit of a grass flower cluster, or inflorescence, is a spikelet (illustration from wikipedia). The bottom pair of bracts are sterile and are called glumes. The florets are embraced by two more bracts, the palea and the lemma. During flowering, the palea and the lemma are forced apart to expose the stamens (male, pollen-bearing parts, of which there are usually 3 but sometimes 6) and stigmas (female, egg-bearing part, which is feathery). (zipcodezoo)

Here’s Lasiacis (click on the image for a larger view)

Six stamens (some of which have burst and are showing pollen grains) and a feathery (or wooly) part, which may be the stigma.

…that are Wind-pollinated

The (relatively) huge stamens just bursting with pollen make it easy for Lasiacis, like other grasses, to be wind-pollinated. No doubt, the wooly tip of the flower helps capture wind-borne pollen from other Lasiacis plants.

Grasses also have Fruits

The fruit is usually a caryopsis (from Greek karuon ‘nut’ + opsis ‘appearance’) – dry and one-seeded. (zipcodezoo)

Here’s the Lasiacis fruit:

When the fruit is still green it will stick to your skin and clothes…like burrs. But this ripe black fruit does not stick. The grid, by the way, is 1/4 inch x 1/4 inch (6.35 mm x 6.35 mm).

…and that of Lasiacis is unique

Doesn’t this fruit look like a berry, admittedly a small one, but a berry, nonetheless? No other grass has a black fruit like this. It also contains oil, another feature unique among the grasses. The combination of a berry-like appearance and the nutritional value of oil means that birds will eat the fruits and thus aid in dispersal of Lasiacis – which may account for it showing up before other grasses on that disturbed patch of ground!

In summary, then, we know Lasiacis is a grass because it has the features of the family:

• Hollow stems
• Base of leaves wrapped like a sheath around the stem
• Alternate leaves
• Parallel veins
• A grassy inflorescence
• Pollination by wind

It is also unique among the grasses by having an oily, black fruit that is eaten by birds, thus dispersing its seeds.

So, next time you’re walking about in Panama, keep an eye open for a broad-leafed grass with velvety leaves, and enjoy.