Fig. 336. 



CHAPTER XXXI. 



QUILLWORTS (ISOETES). 



589. The quillworts, as they 

 are popularly called, are very 

 curious plants. They grow in 

 wet marshy places. They receive 

 their name from the supposed 

 resemblance of the leaf to a quill. 

 Fig. 336 represents one of these 

 quillworts (Isoetes engelmannii) . 

 The leaves are the prominent 

 part of the plant, and they are 

 about all that can be seen except 

 the roots, without removing the 

 leaves. Each leaf, it will be 

 seen, is long and needle-like, ex- 

 cept the basal part, which is 

 expanded, not very unlike, in out- 

 line, a scale of an onion. These 

 expanded basal portions of the 

 leaves closely overlap each other, 

 and the very short stem is com- 

 pletely covered at all times. Fig. 

 338 is from a longitudinal sec- 

 tion of a quillwort. It shows 

 the form of the leaves from this 

 view (side view), and also the 



Isoetes, mature plant, sporophyte stage, general outline of the short Stem, 



which is triangular. The stem is therefore a very short object. 



289 



