318 



OHIO EXPERIMENT STATION: BULLETIN 175. 



82 Lady's=thumb, Smartweed (A) * Polygonum Persicaria L. The 

 lady's-thumb is smaller than the last, 12 to 18 inches high, with smooth peduncle 

 and leaves Often marked with a dark triangular or crescent-shaped spot near 

 the middle. It is attacked by the septoria already mentioned, and also harbors 

 the corn-root aphis, according to Forbes, the louse appearing with the first 

 leaves of the plant. 



Seeds much smaller than the last, lens-shaped or triangular. Found in near- 

 ly all clover seed, from which the seeds cannot well be separated by screening. 

 It can be destroyed by preventing it from seeding and by sowing only clean 

 seeds. When such plants occur in fields to be cut for clover seed they should 

 first be removed. 



83 Smartweed, Water Pepper (A) ^Polygonum Hydtopiper L. This is 

 a smooth, erect smartweed, often reddish in color. The leaves are lance-shaped 

 while the stem grows to a height of one to two feet. The spikes are nodding, 

 often uninterrupted. The seeds are dull, not smooth and shining as in the 

 others. The plant is frequently naturalized in moist places and may be accom- 

 panied by the mild water pepper, Polygonum hydropiperoides Michx. 



84 Prince's Feather (A) ^Polygonum orientale L. Also grows as an 

 escape from cultivation. The more pronounced flower-cluster will distinguish it. 

 The seeds are usually dull, almost circular in outline with point at apex, thick 

 lens-shaped, 1-10 inch in diameter. 



85 Black Bindweed (A) * Polygonum Convolvulus L. Black bindweed is 

 a twining or running annual with leaves shaped like buckwheat and with 

 similar seeds. It is very abundant in bottom lands, where, by overflow, it may 

 be distributed widely. Also found in cultivated grounds. It is attacked by two 

 or more species of leaf fungi . 



Seeds dull black, triangular, 1-8 in. long, occasionally found in grain. It 

 has been especially complained of in bran from western mills. To be rid of 

 black bindweed it seems necessary to remove fences and borders of brush and 

 to employ the scythe and torch in destroying plants and seeds. 



86 Tear=thumb (A) Polygonum arifo limn L., Polygonum -sagUtatutn *L. 

 These two species, the first halberd-leaved, the second arrow-leaved, are often 

 found in low grounds, and make themselves especially known by the prickles 

 on the stems and leaf-stalks. The seeds may come in commercial products; 

 (See weed cuts for latter sort). Destroyed by drainage and by the methods 

 recommended for the last. 



GOOSEFOOT FAMILY, CHENOPODIACE/E. 



87 Lamb's=quarters, Goosefoot (A) * Chenopodium 

 album L. Lamb,s-quarters, Fig. 17, is a common annual 

 weed in cultivated lands. It grows from two to six feet 

 in height but more commonly, two to three feet. The whole 

 plant is more or less mealy in appearance. It is some- 

 times called pigweed, which name more properly belongs 

 to the amaranths. The young and tender plants are used 

 by southwestern Indians as pot-herbs, but with us the}' 

 are not made use of. 



It is attacked by several species of fungi, including 

 Cercospora dubia (Riess. ),Septotia Westendorpii Wint., and 

 Petonospora effusa (Grev. ) Rabh. ; the latter fungus is 

 destructive to spinach. With smartweed, ragweed and 

 sorrel it harbors the adults of a smalt striped beetle, 

 Systena tceniata, which is destructive to beets and mangel- 

 wurzels. The larvae of this beetle also work upon the 

 roots of these plants. This and No. 83, also harbor the 

 melon louse, Aphis gossypii Glov., according to Pergande. 



Fig. 17. Lamb's 

 quarters. 

 {.After Mittspaugh. 



