16 ELEMENTS OF BOTANY. 



perianth of fine bristles ; staminate flowers sessile ; stamens 

 2-7 ; filaments connate, subtended by minute bracts ; pistil- 

 late flowers short-pediceled ; ovary 1-2-celled ; styles 1-2 ; 

 fruit small, nut like. 



TYPHA. 



Characters of the family. 



T. LATiFOLiA L. Cat-tail. Stem erect, jointed below, 5-8 ft. 

 high ; leaves nearly as long as the stem, about 1 in. wide, reticulated 

 and glaucous ; spike cylindrical, dark brown or black ; staminate 

 and pistillate portions usually without any interval between them, 

 each 4-8 in. long and about 1 in. in diameter ; fruit furrowed. June- 

 August. Common in marshes and shallow ponds. 



3. ALISMACEJE. WATER-PLANTAIN FAMILY. 



Annual or perennial marsh herbs, usually with creeping 

 runners or rootstocks ; stems scapose ; leaves long-petioled, 

 sheathing at the base ; petiole rounded; blade nerved, reticu- 

 lated, or sometimes wanting ; flowers in racemes or panicles, 

 perfect, monoecious, or dioecious ; pedicels in bracted whorls ; 

 sepals 3, persistent, petals 3 or wanting; stamens 6 or more, 

 ovaries few or many, 1-celled, 1-seeded ; style short or none ; 

 fruit a 1-seeded achene. 



L ALISMA. 



Annual or perennial herbs, leaves erect or floating, blades 

 prominently ribbed and reticulated, or even pinnately veined ; 

 scapes erect, becoming longer than the leaves, terete, spongy ; 

 flowers perfect, in paniculate 3-bracted umbels, small, white 

 or pink ; stamens 6-9 ; ovaries numerous in one or more whorls 

 on a flat receptacle ; fruit 1-seeded achenes which are ribbed 

 on the back and sides. 



A. Plantago-aquatica L. Water Plantain. Perennial ; 

 root fibrous ; leaves ovate or somewhat cordate, 5-7-nerved when 

 erect, floating leaves narrower and sometimes linear ; scapes usually 

 single ; panicle 1-2 ft. long ; flowering branches whorled, subtended 

 by three narrow, striate bracts ; pedicels slender, elongated ; ovaries 



