EARLY SUMMER FLOWERS 209 



the conveyance of pollen by the wind may be instructively 

 compared with those in the Field Woodrush (p. 52), an unrelated 

 plant which grows in similar situations. 



THE CHARLOCK (Brassica sinapis, Visiani). 



The Charlock is one of the commonest and most abundant 

 weeds of cornfields and other cultivated ground. From May 

 onwards whole fields may appear bright yellow owing to its 

 flowers, and even when less abundant specimens can readily 

 be found. The plant is an annual one, growing up from seed 

 in the spring, and reaching its full size, which varies according 

 to the conditions from a few inches in ill-nourished specimens to 

 two feet in strong, branched examples. The plant bears numerous 

 flowers, and fruits freely. The seeds shed from the fruits remain 

 in the soil and give rise to the crop of the next spring. Such 

 annual plants, in which the individuals do not persist from year 

 to year, are dependent on an abundant production of seed for 

 their success in competition with others. They are not well 

 suited to take possession of ground already occupied with a 

 close growth of plants, but find suitable conditions in the bare 

 soil of cultivated fields. Many of the weeds of our gardens and 

 crops are annual plants. 



The Charlock is best studied in a fully grown plant bearing 

 flowers and fruits. It has a stout tapering tap-root, which grows 

 vertically down into the soil and gives off slender, branched, lateral 

 roots. The main stem of the plant bears a number of fairly large 

 leaves, which are situated singly at the nodes and are separated 

 by long internodes. The stem is green, cylindrical, and slightly 

 ribbed, and its surface bears short, stiff, white, bristly hairs. The 

 leaves have a short, wide stalk, hardly distinguishable from the 

 leaf-base, and a leaf-blade, which is either oval with a toothed 

 margin or more deeply divided into pinnate lobes. Stiff hairs are 

 sparingly scattered on both surfaces and at the margin. After 

 bearing the two seed-leaves, which may be found at the lowest 

 node even in mature plants, and four or five foliage-leaves, the 

 main shoot of the plant continues as an inflorescence. In strong 

 plants the buds in the axils of several of the foliage-leaves develop 



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