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Witkate Y : ‘ ys io Pow es a) Me Us 
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Lapel ‘ \ : ( , ¢ \ Mathes 
138 ILLINOIS ACADEMY OF SCIENCE 
Caryopsis inclosed with scales having transverse stri- 
ations. 
Straw colored, striations branched. Setaria glauca. 
Green, striations faint. Setaria viridis. r, 
Seed minutely pitted, ovoid to spherical. Cuscuta arvensis. 
Seed with faint radiating striations. Chenopodium album. 
17. Lens shaped. 18. 
Not lens shaped. 19. 
18. Seeds circular, .7 to .9 mm. Amaranthus graecizans. 
Seeds obovate, 1 to 1.2 mm. long. Amaranthus retroflexus. 
19. Groove on one side, grain reddish brown. Bromus seca- 
linus. , 
No groove on one side. 20. 
20. Achene seal brown, polished, ovoid. Ambrosia artemisii- 
folia. | 
Achene tan, cup shaped at apex. Cirsium arvense. 
DESCRIPTIONS 
GRAMINEAE. Grass family 
Seraria GLaAuca. (lxophorus glaucus.) Yellow fox-tail. 
Pigeon grass. After rubbing, the spikelet consists of a grain or 
_ caryopsis and two firm coverings called respectively lemma and 
palea. This seed-like structure is straw colored, concave on 
one side and very convex on the other; prominent transverse 
striations mark the surface of the lemma and palea; apex 
slightly three toothed; 2.5 to 3 mm. long and 1.5 mm. in 
diameter. Common impurity in clover, millet, alfalfa and 
timothy. Plate T. } 
SETARIA ViRDIS. (Ixophorus viridis.) Green fox-tail. This 
seed-like structure, as in Setaria glauca, consists of a grain or 
caryopsis and two firm coverings. It is green, having the sur- 
face marked by faint transverse striations; 1.5 mm. to 2 mm. . 
long and .8 mm. in diameter. Common in clovers, alfalfa, and 
millet. Plate I. 
DIGITARIA SANGUINALIS. (Syntherisma sanguinalis.) Fin- 
ger grass. Large crab grass. After severe rubbing, the spikelet 
consists of a grain or caryopsis and two firm coverings— 
lemma, which is on the convex side, and palea. It is straw col- 
