PILTTLARTA.] MAESILEACE^. 527 



placentas many membranous sacs, enclosing macrospores and microspores. 

 DISTRIB. Temp, andtrop. regions ; genera 2 ; species 40. AFFINITIES. 

 With. Selaginellacece. 



1. PILUIiA'RIA, L. PlLLWORT. 



Eootstock filiform, creeping. Leaves subsolitary, erect, setaceous. Cap- 

 sule globose, 2-4-celled, 2-4-valved at the top ; cells each with a longi- 

 tudinal parietal placenta, on which are inserted many pyriform mem- 

 branous sacs ; sacs in the upper part of the cell full of microspores im- 

 mersed in mucilage ; those in the lower part contain each one macrospore. 

 Microspores globular, full of antherozoids. Macrospores ovoid, with an 

 outer coat of prismatic cells, pierced by a funnel-shaped opening, through 

 which an inner glassy coat finally protrudes. DISTRIB. N. and S. 

 temp, and cold regions ; species 3. ETYM. pilula, from the form of the 

 capsule. 



In germination a prothallus is developed at the top of the protruded 

 portion of the inner coat of the macrospore, which bursts and frees it. 

 After expulsion an archegonium is formed on the prothallus, and fertili- 

 zation takes place by the contents of the microspore. 



P. globulif'era, L. ; leaves setaceous, capsules pubescent. 

 Edges of lakes and ponds, from Skye and Sutherland to Cornwall and Hants ; 

 N.E. and W. of Ireland, very rare ; frt. June- Aug. Rootstock or stem 2-6 

 in., glabrous, cylindric. Leaves 2-4 in., green. Capsules J in. diam., ovoid 

 or globose, shortly pedicelled, in the axils of the leaves or on the rootstock 

 pubescent, brown, 4-celled. DISTRIB. Europe N. of the Alps. 



