THALAMIFLOR^ 107 



rarely be insect-pollinated, e. g. by flies, if they open. 

 But they are often closed, and cleistogamic, being 

 self-pollinated under water. The anthers and stigma 

 mature at the same time. According to Hildebrand 

 they remain closed, and are self-fertile when the 

 water is above the usual level. 



The pods opening under water the seeds are 

 dispersed by the agency of the water. 



The only other name is Glond. 



SuBULARiA AguATiCA. — III Fig. 15 the general habit 

 of the Awlwort is shown ^ with its quill-like or awl-like 

 leaves, adapted to aquatic conditions. The shortly- 

 stalked pods are also shown. 



Penny Cress {Thlaspi arvense). 



Like many other Cruciferous plants, which are 

 rich in nitrogenous reserve-materials, Mithridate 

 Mustard, as Penny Cress is also called, is a colonist, 

 according to Watson, and grows only where it has 

 followed in the wake of man and the plough. 



All parts of the British Isles furnish evidence of 

 the extension of this plant within the limits of culti- 

 vation. It is, however, not so widespread in Scotland, 

 and in Ireland appears to be confined to the Eastern 

 counties. It is found also in the Channel Islands. 

 Apparently it is more frequent on the Continent 

 than with us. 



The habitat of this plant is cornfields (hence 

 arvense), cultivated ground generally, waste places. 



