Monsoon showers bring summer flowers


Last month, September 30-October 5, a group of fellow Portal enthusiasts (Zachary Brym, Katherine Thibault, and Christa Weise) got together at the site to take on not only the rodent survey, but also the summer annual and perennial plant survey. Each experimental plot (50 m X 50 m) also has 16 (0.5 m X 0.5 m) permanent plant sampling quadrats within it so that we can understand what changes might occur in the plant community from year-to-year or based on differences in what rodents might be munching or moving around their seeds. We weren’t sure that we could actually finish the survey between our schedule flights to Arizona, but found that a determined group of (mostly) mammalogists could actually do pretty well at identifying desert plants!

There doesn’t seem to be a great field guide for the plant occurring at the site (barely in Arizona, almost in New Mexico, and a desert transition zone…) but we compiled a small ‘library’ to take out with us including a mini-herbarium of plants pressed over the years, the Flora of New Mexico book, Flora of Arizona Book (Epple), and the Peterson Field Guide to Southwestern and Texas Wildflowers, and a Grasses of Arizona Book. We’d love to hear any suggestions for other guide books for the area, especially for grasses or non-flowering ID characters.

The weather was great and by working all day everyday, we were able to sample all our rodents (still a desert pocket mouse takeover) and get to all the plant quadrates with very few unidentifiable individuals! The area near the Chiricahua mountains seems to have gotten more monsoon rain that many other areas of southeastern Arizona, so there were quite a few plants to count relative to some other years, and I would guess (haven’t finished entering data yet!) that there were about 15 species of annual plants per plot. This is actually relatively high diversity for this site, since many years have less than 5 species present! Most common was the Summer Poppy (Kallstroemia grandiflora), Woolly Tidestromia (Tidestromia lanuginosa), two species of spiderling (Boerhavia intermedia and torreyana) and panicum grass (Panicum arizonicum and hirticaule). We tried to photo document everything identified (and unidentified!) and hope to update our mini-herbarium soon since many of the samples are becoming worse for the wear.

It was a lot of work and a cobbled together fast trip, but we sampled everything and had a lot of fun!

This is a photo of plot 16 showing the vegetation this year. It may look sparse, but its a lot more vegetation than in the last few seasons!

Pit tagging a small desert pocket mouse, Chaetodipus penicllatus.

Kate gets reacquainted with the rodents.

Working on identifying plants in a quadrat, with Christa Weise.

Using the herbarium cards to identify a more rare species this year, Euphorbia micromera.

This is an unidentified carpetweed, Kallstroemia spp. It was really common this year...Any ideas?

Some of the grasses are tricky! We brought back samples of this one, but couldn't decide if it was Eragrostis arid or intermedia. We left the site leaning more towards intermedia.

Zack Brym, Kate Thibault, and Christa Weise work hard on an especially grassy sampling site.

We were lucky to get showers each afternoon to cool things down.

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4 Responses to “Monsoon showers bring summer flowers”

  1. Nathan Taylor Says:

    The Euphorbia is actually Euphorbia serpyllifolia. The leaves appear to be serrated and the stems are slightly ascending along with other characters.

  2. Morgan Ernest Says:

    Hi Nathan. Thanks for your input on the id. We are working with the University of Arizona herbarium to confirm our species IDs for plants at our site. Don’t suppose you can ID the other ones in the photos that we were having problems with?

    • Nathan Taylor Says:

      I’m not sure on the grass, but I think the Kallstroemia is K. hirsutissima because of the hairs on the stems and leaves and the somewhat conical beak of the fruit. In K. californica, the stems are like this but become glabrate while K. hirsutissima is more densly hairy. I’m mainly basing this off the descriptions in Manual of the Vascular Plants of Texas (which includes all species of Arizona) so definitely take my suggestion with a grain of salt. I haven’t seen either in person (that I’m aware of).

      In case you’re interest in more details on the Euphorbia, E. micromera is one of only a few species in the area that has ovate leaves rather than oblong or oval leaves. This one has more oblong leaves like E. abramsiana or E. glyptosperma.

      • Morgan Ernest Says:

        You’re awesome! I don’t think the Manual of Vascular Plants of Texas is one of our books (we have books for AZ and NM, but not TX I think). Will have to get that one. Thanks so much for your IDs. I’ll pass them along to my project manager so she can check to see if they are still unknowns in the database and change accordingly.

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