Elymus lanceolatus
Elymus lanceolatus. Florets with sparsely hispid or short pubescent hairs on the callus. 

Elymus multisetus
Elymus multisetus. Florets are smooth with scabrous awns.

Elymus multisetus
Elymus multisetus. Florets are smooth with scabrous awns and a narrow and glabrous rachilla.

Elymus mutabilis
Elymus mutabilis. Florets with a short awn and the lateral sides of the callus have hispid hairs.

Elymus patagonicus
Elymus patagonicus. Florets with lanceolate lemmas and a small hump near the callus.

Elymus repens
Elymus repens. Florets with a strongly spaced palea margin teeth, a ridge up the center of the palea, a hump at the base of the lemma, and a parallel-sided rachilla that terminates in a U-shaped sinus. Photo by Julia Scher, USDA-APHIS-PPQ.

Elymus repens
Elymus repens. Florets with pointed glumes that have lumps where they join at the base. Photo by Julia Scher, USDA-APHIS-PPQ.

Elymus repens
Elymus repens. Spikelet. Photo by Julia Scher, USDA-APHIS-PPQ.

Elymus repens
Elymus repens. Smooth and glabrous florets.

Elymus repens
Elymus repens. Florets with strongly spaced palea margin teeth, a ridge up the center of the palea, a hump at the base of the lemma, and a parallel-sided rachilla that terminates in a U-shaped sinus. 

Elymus trachycaulus
Elymus trachycaulus. Florets with fine hair that is continuous over the callus and a pubescent rachilla. 

Elymus virginicus
Elymus virginicus. Florets are mostly glabrous with some scabrous hairs at the tips. 

Elymus virginicus
Elymus virginicus. Spikelets have two large, thick, and bowed glumes that often stay associated with the basal floret.  

Emex australis
Emex australis. Achenes with three sharp spines at the apex. 

Emex australis
Emex australis. Achenes with hard and woody floral parts with irregular cavities. Photo by Julia Scher, USDA-APHIS-PPQ.

Emex spinosa
Emex spinosa. Achenes are hard and woody with irregular cavities. 

Emex spinosa
Emex spinosa. Achenes with three spines at the apex. 

Emex spinosa
Emex spinosa. Achenes with persistent floral parts. Photo by Julia Scher, USDA-APHIS-PPQ.

Encelia californica
Encelia californica. Achenes are covered with appressed hairs.

Engelmannia peristenia
Engelmannia peristenia. Achenes with bracts that give a winged effect on the ventral side. 

Engelmannia peristenia
Engelmannia peristenia. Achenes with a dorsal side that has two calyx scales. 

Ephedra nevadensis
Ephedra nevadensis. Achenes with calyx fragments that may be attached.

Ephedra viridis
Ephedra viridis. Achenes with an apical rim and a longitudinal flat surface. 

Eragrostis cilianensis
Eragrostis cilianensis. Caryopses are moderately translucent.

Eragrostis cilianensis
Eragrostis cilianensis. Lateral view of fruit. The caryopses naturally rest on their sides since they are laterally compressed. Photo courtesy of USDA-APHIS-PPQ.

Eragrostis cilianensis
Eragrostis cilianensis. Lateral view of spikelet. Remnant of the top of a spikelet. Note long cilia on palea veins. Photo courtesy of USDA-APHIS-PPQ.

Eragrostis curvula
Eragrostis curvula. Caryopses with a yellow-brown endosperm and the scutellum of the embryo is blue-green. 

Eragrostis curvula
Eragrostis curvula. Florets in ventral view. The brown caryopses can be seen through the ± translucent paleas. Photo courtesy of USDA-APHIS-PPQ.

Eragrostis lehmanniana
Eragrostis lehmanniana. Caryopses with a green embryo scutellum. 

Eragrostis tef
Eragrostis tef. Caryopses with an embryo that is approximately two-thirds the length of the caryopsis.

Eragrostis tef
Eragrostis tef. Caryopses with a light brown scutellum.

Eragrostis trichodes
Eragrostis trichodes. Caryopses with the embryo over half the length of the caryopsis. 

Eragrostis trichodes
Eragrostis trichodes. Caryopses with a deep cavity on the ventral side that are open to the basal end.

Eremochloa ophiuroides
Eremochloa ophiuroides. Caryopses and spikelets. Photo by Steve Hurst, USDA Natural Resources Conservation Service.

Eremochloa ophiuroides
Eremochloa ophiuroides. Caryopses with a scar on the ventral side of the base. 

Eriastrum densifolium
Eriastrum densifolium. Seeds with a small basal end that is a pointed circumference.

Ericameria nauseosa
Ericameria nauseosa. Achenes are covered with silky pubescence, and the pappus spreads as long as the achene. 

Erigeron speciosus
Erigeron speciosus. Achenes are covered with short appressed hairs.

Erigeron speciosus
Erigeron speciosus. Achenes with a long, barbed pappus that is usually broken down to short bristles.

Erigeron strigosus
Erigeron strigosus. Achenes with a long, barbed pappus that is usually broken down to short bristles.