I really, really don't want to go down the grass ID rabbit hole. There are more than 300 grass species in New Mexico, and they don't have obvious flowers. But from time to time I'll take and post pictures, in part to learn and in part to share what I think I've learned. If you see a mistake, please click on the Contact tab to let me know.
If your "grass" has a stem that's triangular in cross section, it's a sedge.
The images are in alphabetical order by genus and species. Hover over a photo series with your cursor to control the images.
Sideoats Grama (Bouteloua curtipendula)
This species puts out stalks from which the flowers (and later the seeds) hang.
Blue Grama (Bouteloua gracilis)
This grama grass puts up a stalk, with the flowering part out to one side (other species of grama grass do the same). A few New Mexicans have created puffy lawns out of this species but its ordinary habit is to grow in discontinuous clumps.
There are 14 documented species of Bromus in Bernalillo County alone. I'm already climbing out on a limb by taking the ID to genus, so no way I'm drilling down to species.
Feather Fingergrass, Zacate Lagunero (Chloris virgata)
Large Barnyard Grass, Zacate de Agua (Echinochloa crus-galli)
Large barnyard grass is an Old World species that has spread around the world. I found clumps of this grass with its distinctly purple panicles (clusters of flowers) along a high-water channel of the Rio Grande, and on the bank of the main channel.
Slender Wheatgrass (Elymus trachycaulus)
Arizona Fescue (Festuca arizonica)
This seems to be the signature grass of the upper Sandia Mountains, including in the ski runs.
Feathertop (Pennisetum villosum)
A non-native species, introduced to the New World from the old as an ornamental. I found it next to a channel of the Rio Grande; presumably the first seed washed downstream.
Carrizo, Common Reed (Phragmites australis)
This patch of carrizo is growing next to an irrigation drainage ditch, itself next to the National Hispanic Cultural Center.
Common Panic Grass, Witch Grass? (Panicum capillare)
My photos document two encounters with what I think is common panic grass. In the open space at the western base of the Sandias, I encountered puffy mounds of grass with airy panicles. In August, the panicles still had a purple tinge; a month later they were dry and brown. In September also found the same grass, still green, among taller wetland plants at the edge of a nature pond. In one picture from the latter set, there appears to be a small cloud in the grass. This effect was produced by dew-covered panicles sparkling in the sun.
Ravenna Grass, Elephant Grass (Saccharum ravennae)
This taller-than-you-are grass is reminiscent of pampas grass (Cortaderia selloana), but is hardier (it is sometimes sold under the name "hardy pampas grass"). One difference is that pampas grass flower/seed stalks barely rise above the clump of leaves, while Ravenna grass flower/seed stalks extend well above the clump of leaves. Ravenna grass is exotic and invasive, and common along the local stretch of the Rio Grande.
Johnson Grass, Johnsongrass (Sorghum halepense)
Johnson grass (one or two words) was imported from the Old World as a source of hay and forage, but is invasive and potentially harmful to cattle. According to the SEINEt web page for this species, it's "commonly found along irrigation ditches and in floodplains in the Southwest." I found this clump at the mouth of Tijeras Arroyo.