Excerpts from Jim Conrad's
Naturalist Newsletter

Sunflower Goldeneye, VIGUIERA DENTATA

from the January 2, 2011 Newsletter issued from Hacienda Chichen Resort beside Chichén Itzá Ruins, central Yucatán, MÉXICO
SUNFLOWER GOLDENEYES IN SUN & WIND

Hiking to Pisté to buy bananas and oranges I decided to check out an abandoned field along the way. Back in college I had a special interest in "old field succession" -- how distinct communities of plants successively displace one another between when a field is abandoned and when it reverts to a secondary woods. This time last year the Pisté field had been covered with knee-high annual herbs and grass, so what would it look like this year?

The change was striking. The most conspicuous plant, in some places forming house-size thickets, was a bushy, eight-ft-high (2.4m) member of the Composite or Sunflower Family absolutely loaded with inch-wide (2.5cm), yellow blossoms. It was a dazzlingly sunny day with a stiff breeze, and how pretty it was to stand beside the plants watching their golden heads heave in the wind. You can see a small part of a plant at the top of this page.

The other day a visiting botanist told me that the Yucatán's composites -- plants in the Composite or Sunflower Family -- were driving her crazy, since there are no field guides or identification keys for them. One reason the Composite Family is such a challenge is that there are so many of them. In the adjacent state of Quintana Roo about 90 species in the family have been listed, and there must be a similar number here. In Quintana Roo the Composite Family is the third most diverse family, after the Bean Family (±146 species) and the Grass Family (±101 species).

Composites are a problem for me, too, but that day I decided to try on this spectacular species.

Keeping in mind the key field marks distinguishing genera and species in the Composite Family, I systematically noted the yellow-flowered bush's features. First I looked beneath the flower head and saw that the green scales, or phyllaries, overlapped one another in three or so series, and were expanded at their bases and with sharp, herbaceous tips, shown below:

Sunflower Goldeneye, VIGUIERA DENTATA, involucral bracts

Next I broke apart a flower head to see if individual flowers inside the head were separated from one another by scales (also called bracts or paleae). I found many unusually wide, sharp pointed ones, shown below:

Sunflower Goldeneye, VIGUIERA DENTATA, paleae or scales around achenes

Next I needed to know what kind of "pappus," if any, crowned the plant's one-seeded, seedlike achene-fruits. Pappi on mature achenes eventually mature into fuzzy, wind-catching parachutes, spines that stick into fur, or several other configurations, all designed to help the fruit get disseminated. You can see what I found atop three achenes below:

achenes with aristate and lacerate scale pappi, of Sunflower Goldeneye, VIGUIERA DENTATA.

Each achene bore a pappus in a different state or repair. The pappus of the one on the left is complete, consisting of two long, sharp, broad-based spines, plus a crown of four or so jagged-topped (lacerate) scales, and these surround the old, drying-up disk- flower about ready to fall off. On the middle achene the flower and one long, sharp spine have fallen off. On the achene at the right just the crown of four or so lacerate scales remains. Maybe these sharp-pointed scales help the achenes stick to passing animals.

Finally I looked at the leaves, and one is shown below:

Sunflower Goldeneye, VIGUIERA DENTATA, leaf

The leaves are conspicuously three-nerved from their bases, plus their blades form "wings" extending part of the way down the petioles. Leaves on the plant were all "alternate" -- one leaf per stem node -- but scars on the stem at the plant's base indicated that the first leaves may have been "opposite" -- two leaves per stem node.

With these field marks noted and documented I was able to get a name, thanks especially to the fact that the species also occurs in the US's southwestern desert, so the species is keyed out and described in the online Flora of North America.

Among the plant's English names are Sunflower Goldeneye and Toothleaf. It's VIGUIERA DENTATA, a genus that on the phylogenetic Tree of Life stands near the sunflower genus Helianthus.

It also grows in Cuba and Central America. In this part of the world it's pretty common in weedy areas.


from the January 22, 2012 Newsletter issued from Hacienda Chichen Resort beside Chichén Itzá Ruins, central Yucatán, MÉXICO
YELLOW ROADSIDES

Nowadays the road south of Pisté toward Yaxuná is resplendent with a yellow-flowered, weedy wildflower sometimes called Sunflower Goldeneye, Viguiera dentata. You can see how the yellowness just stretches on and on below:

Sunflower Goldeneye, VIGUIERA DENTATA, en masse along roadside


from the January 31, 2016 Newsletter issued from Hacienda Chichen Resort beside Chichén Itzá Ruins, central Yucatán MÉXICO
SUNFLOWER GOLDENEYE AT PEAK OF PERFECTION

Last summer on some days as hot and humid as it gets here, you may recall how as we walked the empty highway between Yaxunah and Kancabdzonot I commented on the chest-high super-abundance of Sunflower Goldeneye's green stems and leaves, wistfully looking forward to the cooler, drier days when the plants would make gorgeous, ten-ft-high (3m), flowery walls along the roads. Those days now have come. You can see a detail below:

Sunflower Goldeneye, VIGUIERA DENTATA