2 ENGLISH BOTANY. 



open protruding neck : the male organs consist of spiral ciliated 

 threads {antherozoids), produced from cells (antheridia), either formed 

 upon or in the prothallium or contained in separate spores from those 

 which produce the prothallium which developes the archegonia. 



ORDER LXXXIX.— M ARSILIACEjE. 



Aquatic or marsh plants with creeping rooting branched root- 

 stocks. Leaves alternate, erect, filiform, without any lamina, or with 

 a lamina composed of 4 equal, obovate, entire or retuse leaflets ; in 

 either case with circinate vernation. Sporangia contained in cap- 

 sules or sporocarps, subsessile in the axils of the leaves or more or less 

 longly stalked and springing from the lower part of the leaf, globular 

 or ovoid, often hairy at least when young, 2- to 4-celled vertically, 

 2- to 4-valved. Spores of two kinds, the larger (inacrosjwres) solitary 

 in each macrosporangium, the smaller (microspores) numerous in 

 each microsporangium. Macrosporangia and microsporangia included 

 in the same sporocarp. Prothallium developed from a papilla at the 

 apex of the macrospcre ; its oosphere, after being fertilised by the 

 antherozoids discharged from the microspores, developes and forms 

 I lie new plant. 



GENUS /.— PILULARIA. Linn. 



Sjiorocarps subglobular subsessile and erect, or shortly stalked and 

 bent down, 2- or 4-celled, 2- or 4-valved at the apex. 



Aquatic herbs, with slender branched creeping stems and setaceous 

 leaves without any lamina. 



Name derived from pilula, a pill, which the sporocarps resemble. 



SPECIES I.-PILUL ARIA GLOBULIFERA. Linn. 



Plate 1825. 

 Rabenhorst, Cryptogams Yasculares Europese Exsiccatte, No. 27. 



Sporocarps subglobose, 4-celled, 4-valved, 3 or 4 times longer than 

 their peduncle, erect. Microspores numerous, ovoid, constricted in 

 the middle. Microspores without a gelatinous covering. 



On the margins of lakes and ponds, usually in shallow water, but 

 left growing in the damp mud in summer. The Rev. W. W. Spicer 

 says, that in September he found it in a pond near Guildford, Surrey, 

 in water 40 inches deep. (Phyt. 1851, p. 3. r >0.) 



