A SECOND OHIO WEED MANUAL. 337 



184 Perennial Vetch (P) Vicia Cracca L. The perennial vetch ts a native 

 of damp thickets. It has extensive rootstocks, rendering- it persistent where 

 once established. In one instance known to the writer the seed had become 

 introduced in grass seed, thus infesting a lawn with the weed. In it the vetch 

 proved a serious pest. It has 20 to 24 rather long- leaflets and is covered with 

 soft down; the flowers are blue turning to purple. 



It can be destroyed only by starving out the rootstocks, through repeated 

 cutting or cultivation. It will require the same persistence in effort as Canada 

 thistle. Care is likewise needed to avoid breaking up the rootstocks and thus 

 scattering the weed thereby. 



GERANIUM FAMILY, GERANIACE^E. 



185 Geranium (A) Geranium spp. Several specimens of European gerani- 

 ums have been found at different points in the state, chiefly in lawns. They 

 are less conspicuous than low mallow, but none the less are weeds. Chiefly 

 annual or biennial. 



186 Storksbill, Alfilaria (A) *Erodium cicutaiium ( L*. ) L' Her. This is a 

 low, hairy plant, with finely divided leaves and conspicuous storksbill fruits. 

 A common weed in the old world and likely to become general with us; at 

 present occasional throughout the state. Seeds elongated, hairy, with long, 

 spirally twisted beak. 



WOOD SORREL FAMILY, OXALIDACE^E. 



187 Yellow Wood=sorrel, Sour=grass (A) Oxalis stticta L. Is the common 

 sour-grass of children, which has three inversely heart-shaped leaflets, usuall}' 

 yellowish green in color. The flowers are bright yellow, the seeds are produced 

 in great abundance. It is a common weed along fences, in lawns and in waste 

 places. Seeds brown, flattened, oval in outline, very small, 1-32 inch long, 

 covered with deep, transverse wrinkles; in hay, etc. This plant requires 

 persistent hand digging to eradicate it. 



FLAX FAMILY, LINACE^E. 



188 Flax (A) *Linupt usitatissimum L. The cultivated flax, with its bright 

 blue flowers and numerous seeds, sometimes occurs in grain and clover. In these 

 situations it is evidently sown with the other seeds and may be prevented by 

 care in this regard. 



AILANTHUS FAMILY, SIMARUBACE.E. 



189 Tree=of=heaven (P) *Ailanthus glandulosus (Desf. ). This tree is 

 much planted in towns. It is a leafy, rank-growing tree whose staminate 

 blossoms have a very offensive odor. The leaves are very long and pinnate, 

 like those of the walnut. It spreads both by seed and from the root. It should 

 not be planted unless the risk of spread has been duly considered. The ailan- 

 thus has been introduced from China. The seed containing fruit is winged, 

 thus rendering it easily carried by the wind. Where extermination is desired 

 frequent grubbing is needed. 



SPURGE FAMILY, EUPHORBIACE.K. 



190 Croton, Hogwort (A) Croton capitatus Michx. This species of Croton 

 native further west and south, was first collected as a waif near Columbus; 

 possibly not general with us. The seeds occur in alfalfa seed and plants thus 

 produced and having mature seeds have been sent for determination. Seeds 

 smooth with suggestive resemblance to those of castor oilplant, brown, semi- 

 globular, about 1-8 inch across. Prevented by avoidance of impure seeds. 



