A SECOND OHIO WEED MANUAL. 



341 



206 Shrubby St. John's=wort (P) Hypericum ptolificum L. It grows in 



dense clusters of upright, shrubby stems, 2 to 4 feet high, in exhausted and 

 sterile, dry fields. The flowers are much like the preceding, and the small 

 wood}- branches are two edged. Should be grubbed out and the land reclaimed 

 by manuring and cultivation. 



LOOSESTRIFE FAMILY, LYTHRACE^C. 



207 Clammy Loosestrife (A) Parsonsia pctiolata (L-.) Rusby. Is a very 

 stick}', red stemmed annual, found throughout southern Ohio. The plant grows 

 about a foot high, has egg-shaped, tapering leaves and small purple flowers. 

 It is most frequent in dry fields and roadsides, occupying similar places to 

 those infested by sida, especially pastures. The conspicuous feature of the 

 weed is its very sticky (viscid) character of leaves and stems. Destroyed by 

 uprooting before the seeds are formed. 



EVENING PRIMROSE FAMILY, ONAGRACE^E. 



208 Water=purslane (P) Isnardia palustris L. This is a prostrate, 

 smooth weed, with small, egg-shaped, reddish leaves. It is very common in 

 ditches and one of the serious pests of muck farms. Where too obnoxious it 

 should be pulled up. 



209 Seed=box (P) Ludwigia alternifolia L. This is a smooth, branched 

 plant, about three feet high, with narrow leaves pointed at both ends, and cubic- 

 al pods with wings at the angles. It is frequent in swampy lands and some- 

 times occurs with spiny sida. Seeds very small, brown, 1-50 inch long and 

 one-third as wide. Destroyed by frequent cutting. 



210 Willow=herb (P) Epilobium spp. The willow-herbs are somewhat 

 downy plants of wet places, one to three feet high, with tapering, sharp-toothed 

 leaves, resembling those of willows. The seeds have a woolly attachment of the 

 seed coat which renders them 

 buoyant. Usually disposed of 

 through drainage and cultiva- 

 tion, by which the land is tamed. 



211 Fireweed, Great Wil- 

 low-herb (P) Chamcenerion an- 

 gustifolium (L.) Scop. Has a 

 very tall, unbranched stem 4 to 

 7 feet high, and scattered, taper- 

 ing leaves. The flowers are 

 showy, bright rose color to pur- 

 ple. It is sometimes very abun- 

 dant in newly cleared lands. 

 Fire seems to induce germination 

 of the seeds protected by a layer 

 of soil; hence the name. The 

 seeds are very small, similar to 

 those of the preceding; they are 

 buoyant and can be transported 

 by the wind. Destroyed by very 

 early cutting or cultivation. 



212 Evening Primrose (B) Fig. 37- Evening- Primrose. 



Onagt a biennis (L. ) Scop. This is a tall, stout, very leafy, somewhat downy 

 or hairy weed usually unbranched, from 2 to 5 feet high, see Fig. 37. The 

 stems are often decidedly reddish; this character is lost when shaded. The 

 leaves are two to six inches long. It has bright yellow, stalked flowers which 

 open in the evening. This primrose is a frequent pest in fields, and by streams 

 and roadsides, where it is generally neglected. 



