102 GROUND FEEDS. 



or colourless outer layer of the seed coat has each cell 

 almost filled with vertical columns of mucilage grouped 

 about a central cavity. Beneath, is the sub-epidermal 

 layer and then the palisade cells, filled with a dark sub- 

 stance which turns red when warmed with concentrated 

 solutions of hydrochloric acid and chloral hydrate 

 in the proportion of one to twenty. Inside the palisade 

 is an opaque, pigmented layer, while the centre of the 

 seed contains oil and aleurone grains. It is here that the 

 poison is located. 



TUMBLING MUSTARD Sisymbrium altissimum L. 



Tumbling Mustard was introduced from Europe about 

 1887, and is an abundant weed in the grain fields of the 

 west owing to its copious seed production and its effici- 

 ent manner of spreading the seeds. When ripe the plant 

 breaks off and is driven by the wind, and the seeds, of 

 which it is reported that there may be as many as 1,500,- 

 000 on a single plant, are spread broadcast- 



The whole plant is dangerous, owing to its pungent oils. 



According to Pammel deep ulcers may be produced by it. 



The vegetative part is not palatable, but the 



seeds often find their way into feeds in 



Poisoning 



quantity. 



Tumbling Mustard is a branching plant, two to four 

 feet high. The root leaves form a rosette, but later 



shrivel and disappear. The stem leaves are 

 aniseed" verv varied and finely dissected. The flowers 



are pale yellow, about one-third of an inch 

 across, and the slender pods are two to four inches long. 

 They are borne as in other Mustards. Introduced from 

 Europe, the plant has spread over the continent and is a 

 very troublesome weed in the north west. 



