PLATE II. 



Each magnified about 5 diameters. 



Nc . 1 Polygonum Convolvulus L Black-bindweed, 4 seeds. 



2 Rumex Acetosella L Sorrel, 4 seeds. 



3 Rumex crispus L Curled Dock, 4 seeds. 



4 Rumex obtusifolius L Bitter Dock, 4 seeds. 



5 Chenopodium album L Lamb's-quarters, 4 seeds. 



6 Chenopodium ambrosioides L Mexican Tea, 4 seeds. 



7 Salsola Tragus L Russian Thistle, 4 seeds. 



8 Atriplex truncata (Torr) A Gray Western Orache, 4 seeds. 



9 Cycloloma atriplici folium (Spreng) Coult — Winged Pigweed, 3 seeds — 1 with covering-. 



10 Amaranthus graecizans L Tumbleweed, 4 seeds . 



11 Amaranthus blitoides Wats Spreading Amaranth, 4 seeds. 



12 Silene conica L Conical Catchfly, 4 seeds. 



13 Silene noctiflora L Night-flowering Catchfly, 4 seeds. 



14 Silene dichotoma Ehrh Forked Catchfly, 2 seeds. 



15 Alsine media L Common Chickweed, 2 seeds. 



16 Cerastium longipedunculatum Muhl Nodding Chickweed, 2 seeds. 



17 Scleranthus annuics'L Knawel, 2 seeds. 



18 Agrostemma Githago L Cockle, 4 seeds. 



19 Dianthus Armeria L Deptford Pink, 2 seeds. 



20 Saponaria officinalis L Bouncing-bet, 2 seeds. 



21 Vaccaria Vaccaria (L) Britt Cow-herb, 2 seeds. 



22 Spergula arvensis L Spurry , 2 seeds. 



23 Ranunculus acris L Buttercup, 2 seeds — 1 with covering 



24 Papaver dubium L Poppy, 4 seeds. 



25 Argemone alba Lestib Prickly- poppy, 2 seeds. 



26 Brassica nigra (L) Koch Black Mustard, 4 seeds. 



27 Brassica arvensis (L) B. S. P Charlock, Wild Mustard, 4 seeds. 



28 Brassica campestris L Turnip, 2 seeds. 



29 Lepidium campestre (L) R Br Field Peppergrass, 4 seeds. 



30 Lepidium Virginicum L Peppergrass, 4 seeds. 



31 Camelina sativa (L) Crantz False Flax, 4 seeds. 



32 Conringia orientalis (L) Dumort Hare's-ear Mustard, 4 seeds. 



33 Erysimum repandum L Spreading Mustard, 4 seeds. 



34 Bursa Bursa-pastoris ( L) Britton Shepherd's-purse, 4 seeds. 



35 Thlaspi arvense L Penny -cress, 4 seeds. 



From original photographs by P. A. HiniAan and J. M. Van Hook. 



