WEEDS AND WEED SEEDLINGS. 



33 



genera in the same order, and by species in the same genus. The 

 cotyledons differ, the first leaves differ, the general appearance of the 

 growing seedlings differs according to species. Some cotyledons are 

 linear and undivided, while others are linear and forked; some are 

 spathulate, some roundish, some oval, some heart-shaped; some are 

 entire but others lobed or even divided, forked or trifid ; in some seedlings 

 the cotyledons are unequal, or the lobes on the same cotyledon are 

 unequal; the cotyledons may be sessile or stalked; the stalks may be 

 fine, or stout and broad; and the cotyledons themselves may be thin, 

 or thick and fleshy. 



Similarly, when the true leaves come to be considered it is found 

 that they also differ exceedingly according to species. It is not proposed 

 to discuss the question of seedlings more fully here, but in dealing below 

 with a few of the commoner weeds the. external characteristics of the 

 seedlings and the differences between them will be noted. 



Some Common Garden Weeds. 



Space forbids a complete review of all weeds, but returns obtained 

 from a number of practical agriculturists in England, Scotland, an(i 

 Wales show that the worst weeds of arable land are, on the whole, the 

 following: — Couch or twitch, charlock, runch, docks, thistles, colts- 

 foot, chickweed, bindweeds, spurrey, poppy, corn buttercup, wild oat, 

 knotweed, fat hen, redshank or Persicaria most prevalent in the order 

 named, followed by a number of other weeds, among which are 

 included groundsel, annual meadow-grass, nettles, cleavers, horsetail 

 and Shepherd's Purse. 



In the same way it was ascertained that the worst weeds of grass 

 land appear to be thistles, buttercups, Yorkshire fog and creeping soft- 

 grass, docks, daisy, plantain, soft brome grass, yellow rattle, sorrels, 

 dandelion, Agrostis sp., knapweed, rushes, nettles, moss, sedges and 

 self-heal. 



Of these weeds it is proposed to refer specifically to the following : — 



Creeping Buttercup 



(Ranunculus reyens) 



Charlock 



(Sinapis arvensis). 



Shepherd's Purse 



{Capsella Bursa-Pastoris) 



Spurrey 



(Spergula arvensis) 



Cleavers 



{Galium Aparine) 



Groundsel 



{Senecio vulgaris) 



Nipplewort 



(Lap Sana communis) 



Burdock 



(Arctium Lappa) 



Dandelion 



(Taraxacum officinale) 



Scarlet Pimpernel 



(Anagallis arvensis) 



Persicaria 



(Polygonum Persicaria) 



Knotweed 



(Polygonum Aviculare) 



Black Bindweed 



(Polygonum Convolvulus) 



Docks 



(Rumex sp.) 



Couch Grass 



(Triticum rep ens) 



VOL. XXXVII. D 



