Irrigation' Water 
13 
TKST N«. 14». DITC H I. 
Date, IHay 27, 101 J>. Diirntfoii, 13 min. 
Species of weed seeds, 17. 
Number of seeds, 302. 
Taraxacum officinale 171 
Chenopodium album 47 
Amaranthus retroflexuis 30 
Amaranthus blitoides 14 
Polygonum aviculare 15 
Iva xanthifolia 7 
Rumex crispus 4 
Polygonum convolvulus 2 
Papaver species 2 
Grindelia squarrosa 1 
Setaria viridis 2 
Verbena bracteosa 2 
Mentha species 2 
Argemone intermedia 1 
Leonurus cardiaca 2 
TKST No. 152. DITCH No. I. 
Date, May 27, 1010. Duration, 15 rain. 
Species of weed seeds, 17. 
Number of seeds, 222. 
Taraxacum officinale 121 
Amaranthus blitoides 17 
Amaranthus retroflexus 10 
Chenopodium album 27 
Polygonum aviculare 11 
Iva xanthifolia 7 
Polygonum convolvulus 4 
Papaver species 4 
Rumex crispus -4 
Setaria viridis 2 
Verbena bracteosa 2 
Helianthus annuus 2 
Echinochloa erus-galli 1 
Polygonum persicaria : 1 
Mentha species 1 
Carex species 1 
Cleome serrulata 1 
TABLE I. — FREQUENCY OF DIFFERENT SPECIES OF WEED SEEDS IN 
156 DITCH SAMPLES 
No. of samples in 
Species which occurred 
Agropyron tenerum — Slender wheat grass 6 
Alopecurus aristulatus — Wolftail 2 
Amaranthus blitoides — Prqstrate pigweed 1 
Amaranthus graecizans — Tumble weed 3 
Amaranthus retroflexus — Tall pigweed 131 
Ambrosia artemisaefolia — Ragweed 21 
Ambrosia trifida — Giant ragweed ^ 10 
Arenaria species — Sandwort 4 
Argemone intermedia — White prickly poppy 13 
Atriplex truncata — Salt bush 1 
Avena fatua — Wild oats 1 
Bidens frondosa — Beggar ticks 1 
Brassica juncea — Indian mustard 1 
Brassica nigra — Black mustard 1 
Bromus inermis — Brome grass 2 
Capsella bursa-pastoris — Shepherd’s purse 6 
Carex species — Sedge 99 
Cleome serrulata — Rocky Mountain bee plant 25 
Chenopodium album — Lamb’s quarter 131 
Echinochloa crus-galli — Barnyard grass 17 
Euphorbia marginata — Snow-on-the-mountain 1 
Franseria tomentosa — Poverty weed 1 
Galium aparine — Cleavers 2 
Geranium species — Geranium 15 
Glyceria species — Manna grass 1 
Grindelia squarrosa — Gumweed 60 
