38 



During the season, 1913-1914, 79 species of plants (herbs, shrubs 

 and trees) came under notice, of which 40 per cent, are included in the 

 three orders, Graminaceas, Leguminosae and Compositae, and a further 

 20 per cent, are in the Umbelliferae and Rosaceae. The herbage is 

 fairly well mixed, as several of the species are plentifully represented, 

 but the dominant species during the early summer months is 

 Arrhenatherum avenaceum, whereas later on in the summer Centaurea 

 nigra is the most conspicuous and dominant plant. 



Geescroft wilderness is densely covered with tufts of the very 

 coarse grass, Aira ccespitosa, studded with a few small trees and shrubs 

 of various kinds. At one end the Aira dominates the situation almost 

 to the exclusion of other plants, whereas at the other end many species 

 have a firm footing in spite of the domiaaaon of this grass. 



Altogether at the present time 88 species (herbs, shrubs, and trees) 

 are to be recognised, of which nearly half are included in three orders 

 (Graminacese, Compositae, Leguminosae), a-nd a further 10 per cent, are 

 in Rosaceae and Umbelliferae. 



At the preseat time the great majority of species are common to both 

 wildernesses, but certain species are peculiar to each. One noticeable 

 point is the abundance of An^hi oxanthum odoratum and Holcus 

 lanatiis m Geescroft, a id their scarcity on Broadbalk. The plants 

 peculiar to Geescroft are characteristic of damp land. Some of them, 

 e.g., Phalaris and Aira, are characteristic of marsh or fen associations ; 

 while those peculiar to Broadbalk arc charac;,eristic of dry meadows. 

 Hedera Helix has probably spread from the thicket. Brachypodium 

 sylvaticum, which is fairly abundanr in the mead )w, is also a woodland 

 grass. The most abundant grasses, Arrhenatherum and Dactylis, are 

 recorded as abundant in the undor^ToWuh cf the " damp oak wood " 

 types, as are many of the other planis in the meadow portion, e.g., 

 Veronica Chamcedrys, Nepeta hederacea, Stachys Betonica. 



XXX. " The Effect of Weeds upon Cereal Crops.'' Winifred 

 E. Brenchlev. New Phytologist, XVI, 191 7. 53-76. 



Wheat and barley were grown in pot cultures a id water cultures in 

 conjunction w4th certain common weeds, inclading poppy, charlock (or 

 white mustard), spurry and black bent. Various combinauons cf the 

 test plants were made over a period of four years. 



When poppy, black bent and spurry were grown with wheat they 

 developed less than when grown alone, showing that they had suffered 

 from the competition of the wheat. The whetU, on the other hand, 

 made more growth per individual pl;i,at than when the weeds \vere 

 replaced by an equal number of wheat plants, indicating that the 

 competition of the wheat with itself when thickly sown is more severe 

 than that of weeds with thinly sown wheat plants. On the other hand, 

 when equal numbers of wheat plants were grown, both with and without 

 weeds, the weedless wheat made much better growth. In these experi- 

 ments spurry proved more harmful than the others, smothering the 

 young wheat by its straggling growth; giving the f lant a bad check 

 from which it never properly recovered. The effect of charlock was 

 rather different from that of the other wv;eds, possibly on account of 

 its habit. The competition between charL)ck arid wheat seems to be 

 nearly equal, and the two plants settled down to some sort of equilib- 

 rium, neither gaining the mastery over the other. Barley, on the 

 other hand, suffered more severely from the presence of poppy, spurry 



