294 COMMON WEEDS 



found in Scotland and Ireland (Hooker). The leaves are 

 five-lobed, light green in colour, and the plant climbs by 

 means of long thread-like tendrils, which twine round 

 other plants for support (Fig. 80). The rootstock con- 

 sists of large fleshy tubers, " sometimes nearly two feet 

 long, thick as a man's arm, white, succulent, and fleshy, 

 with an acrid, bitter, and disagreeable taste " (Henslow). 

 The flowers are quite small and greenish-white, appear- 

 ing between May and October ; they give rise to red 

 berries. Bryony has an unpleasant odour, and contains 

 a milky, nauseous juice. It is a highly irritant plant, 

 and the tuberous roots have been the cause of the 

 poisoning of whole families who have eaten them 

 instead of parsnips and turnips. It has been estimated 

 that forty berries would cause the death of a man, 

 and that fifteen would similarly suffice in the case of 

 children (Cornevin). The toxic principle is a glucoside 

 called Bryonin. 



UMBELLIFER.E 



Several members of this order may be exceedingly 

 harmful either to man or to domestic animals. 



Hemlock (Conium maculatum L.), illustrated in Fig. 

 8 1, a plant which may attain to 5 feet or more. It has 

 a hollow, smooth stem, somewhat glaucous, and more 

 or less thickly dotted with purplish spots. The leaves 

 are large and compound, and the segments are deeply 

 cut, as in most plants of the order. Hemlock grows on 

 banks, near hedges, and by roadsides and streams, and 

 in Yorkshire is found at an altitude of 1000 feet. It is 

 a biennial, and flowers in June to July, the flowers being 

 white and in " umbels." The poisonous principle is at 

 first chiefly contained in the foliage, but later in the 

 fruit, and, as in certain other plants, is largely dissipated 

 when the plant is dried, as in hay. Owing perhaps to 



