138 PATAGONIAN EXPEDITIONS: BOTANY. 



L. SAURURUS Willd. 



Stem simple or bifid, erect, about 30 cm. high. Leaves sparse, about 

 8-seriate, lanceolate, acute, concave, entire, closely imbricate. 

 (Kerguelen, Bourbon, Tristan, St. Helena, Peru) ; Falklands. 



Fam. 10. ISOETACE.E. Quillworts. 



Aquatic or marsh-plants consisting of rosettes of thick grasslike fronds 

 rooting in mud and bearing megasporangia and microsporangia in their 

 swollen, excavated bases. 



Species 50, widely distributed. 



ISOETES Linn. 

 The only genus. 



I. SAVATIERI Franchet. 



Amphibious, the submerged reaching 20 cm. in length ; the emersed 

 about 4 cm. Leaves stout, becoming subtetragonal above and spiny 

 tipped. Sheath broad (7-10 mm.), dorsally sulcate, as if 2-lobed. Macro- 

 spores white, rugose, the rugae anastomosing. Micr-ospores brown, muri- 

 cate, laterally crested. 



Magellan, by lakes near Puerto Bueno ; at Cape Horn ; in W. Magellan, 

 Desolation I. (Dusen). 



