SHAM NETTLES 



make hens lay in winter time. The seeds, under pressure, 

 yield quite a good oil. A yellow dye can be obtained by 

 boiling the roots with alum. An excellent string can also 

 be made from the inner bark of the stems, which has, in 

 fact, been used to make twine and even clothing. The 

 nettle is also valuable as an external stimulant in cases of 

 paralysis. 



A plant with so many wonderful properties would not be 

 so common as it is, or so little disturbed, if it were not for 

 its powerful stings. 



There are one or two plants which are extremely like the 

 nettle at first sight. Lord Avebury has an illustration in 

 his excellent little book^ in which it is most difficult to tell 

 which are White Deadnettles and which are stinging nettles. 

 No doubt the harmless deadnettle is helped to escape injury 

 by this resemblance. The Hemp Deadnettle and some 

 Campanulas are also very like it when growing. These also 

 are sham nettles and may escape in the same way. 



There are several common greenhouse Primulas which also 

 produce irritation of the skin. When handled by gardeners 

 a painful smart is set up which lasts for some time. Primula 

 obconica is the worst of these, but P. sinensis^ P. cortusoides, 

 and P. Sieboldii sometimes have the same effect. In all 

 these cases it is due to a peculiar secretion of certain glan- 

 dular hairs.2 



The methods of protection against grazing animals so far 

 described, such as stinging hairs, thorns, spines, etc. (see 

 page 190), are obvious enough, but perhaps the most 

 ingenious system of defence is that exhibited by the Sensi- 

 tive Plant and a few others. 



* Flowers, Fruit, and Leaves. 



2 Nestler, Sitz. d. K. Akad. d. Wiss, Wien, voL 3, p. 27. 

 N 193 



