316 OHIO EXPERIMENT STATION: BULLETIN 175. 



71 Hemp (A) ^Cannabis sativa L. This annual grows higher than a man; 

 it has divided leaves with tapering pointed segments. The resemblance to the 

 nettles would usually be noticed; hemp has a very tough, fibrous inner bark and 

 is so distinguished; it is grown in the south. Quite common in waste places, 

 particularly about cities and stock yards and liable to become general. Seeds 

 large, quite irregular as to size, ovoid, about 1-8 inch long, varying from dark 

 to lighter with surface markings. May be looked for as an impurity in seeds 

 from the hemp growing districts. Quite frequent in seed oats. 



,NETTLE FAMILY, URTICACE^E. 



72 Tall Nettle (P) Urtica gracilis Ait. This plant is often found in fence- 

 rows and in moist ground, growing 3 to 6ft. tall. It is somewhat bristly, and 

 while it has fewer stings than others, it still has stings. The flowers are in 

 clusters and the leaves are ovate (egg-shaped) and coarsely toothed. Nettle is 

 best destroyed by freqnent close cutting or by cultivation. Seeds small, about 

 1-20 inch long as shown in seed cuts. 



73 Stinging Nettle (P) *Uritica dioica L. This nettle has become introduced 

 at a few places. It is like the other, only very bristly and stinging. It is 

 destroyed by grubbing or cutting. 



Seeds with difficulty distinguishable from the preceding. 



BUCKWHEAT FAMILY, POLYGONACE^E 



74 Curled Dock, Sour Dock, Yellow Dock (P) *Rumex crispus L. The 



curled dock may be recognized by its narrower, curled leaves and other less 

 evident characters. The plant is a bad pest about yards and farm outbuildings. 

 Its large roots make deep cutting necessary; while young, the leaves are used as 

 a pot-herb for "greens." This dock harbors both the melon louse and the corn- 

 root louse. Seeds brown, triangular, 1-12 inch long, two-thirds as wide tapering 

 abruptly to the point, smooth and shining. Very common in clover and alfalfa 

 seed. 



All docks require yearly pulling, deep cutting or grubbing, and this must 

 be done before the seeds are formed. They are also destroyed by cultivation. 



75 Bitter Dock, Broad Dock (P) *Rumex obtusifolius 1j . Broad dock 

 occurs with the last and is very common. It may be distinguished by the broad 

 leaves and more numerous grains on the seed valves. 



Seeds like the curled dock, sometimes slightly darker in color and having a 

 more extended beak, tapering more gradually to the tip. Very common in clover 

 seed. It must be remembered in pulling up docks that the large roots contain 

 enough food to ripen the seeds if the grubbing is left till these begin to form. 



76 Tall Dock, Peach=Ieaved Dock (P) Rwnex altissimus Wood. This dock 

 has a certain resemblance to the others but with distinct botanical characters 

 of leaf and fruit. It prefers moist ground; while a native species it may be 

 found frequently intermingled with the others. Seeds much like the others. 



77 Patience Dock (P) *Rumex Patientia L. A very tall sort of the height 

 of a man, with large leaves and very deep, long root. It is more locally intro- 

 duced than the others, but must be reckoned with among these pesky weeds. 

 Seeds as in the others, about 1-8 inch long, triangular in form. 



78 Sorrel, Horse Sorrel (P) *Rumex Acetosclla L. Sorrel ranks pre-emi- 

 nently as the worst pest of the order on sandy soils. The illustration (Fig. 16) 

 will show the characters of the plant. The whole has a sour taste. It is 

 perennial and abundantly propagated by its running rootstocks as well as by 

 seed. It is apparently confined to sandy soils; these predominate in the coal 

 measures and subcarboniferous districts, where not covered by the drift. 

 This character of formation underlies that part of the state east of a line from 

 Huron on Lake Erie to Rome on the Ohio River below Portsmouth. Sandy 



