FERN FAMILY. 



33 



2. Polypodium polypodioides ( L ) 



A. S. Hitchc 

 Gray Polypody. ( Vi K . 7 



AcrostichumjxilvfKHii.'i.t ..& ,.., 



Polypodium imanum Sw. II i 



i -. ' 



Polypodium /Wr/W/W,/r> \ s i. 



Rep. Mo. Bot . .;inl 4 156. 1895. 



Rootstock widely creeping, woody, cor- 

 ered with small brown scale*. Stipe* dense- 

 ly scaly, i '-3' long; leave* oblong-lanceo- 

 late in outline, acute, coriaceous, cwgieeu. 

 i'-6'long, i'-i#' wide, cut very nearly or 

 quite to the rachis into entire oblong or tin* 

 ear-oblong obtuse segment*, glabrous or 

 nearly so on the upper surface, the lower 

 densely covered with gray peltate scale* 

 with darker centres, a* are also the rachise*; 

 veins indistinct, unconnected and usually 

 once forked. 



On trees or rarely on rocks, Virginia to Flor- 



ida, west to Illinois, Missouri ami Tt-\.is As- 

 cends to 4<> ft. in N'.irth C.t: 

 distributed in tropical America. July-Sept 



Family 6. MARSILEACEAE R. Br. Prodr. Fl. Nov. Holl. i: 166. i8ia 



Perennial herbaceous plants rooting in mud, with slender creeping root- 

 stocks and 4-foliolate or filiform leaves. Asexual propagation consist i: 

 sporocarps borne on peduncles which rise from the rootstock near the '. 

 or are consolidated with it, containing both macrospores and microsjx>res. The 

 macrospores germinate into prothallia which bear mostly archegonia, while the 

 microspores grow into prothallia bearing the antheridia. 



Two genera and some 45 species of wide geographic distribution. 



i. MARSILEA L. Sp. PI. 1099. 1753. 

 Marsh or aquatic plants, the leaves commonly floating on the surface of shallow water, 



. 



slender-petioled, 4-foliolate, Peduncles shorter than the petioles, arising from their 



or more or less adnate to them. Sporocarps ovoid or bean-shaped, composed of two vertical 



valves with several transverse compartments (sori) in each valve. [Name in honor of Gio- 



vanni Marsigli, an Italian botanist, who died about 1804.] 



About 40 species, widely distributed. Besides the following 2 or 3 others occur in Texas. 

 Sporocarps glabrous and purple when mature. >><* 



Sporocarps densely covered with hair-like scales. 



i. Marsilea quadrifolia L,. 



European Marsilea. (Fig. 73.) 



Marsilea quadrifolia L,. Sp. PI. 1099. 1753. 



Rootstock slender, buried in the muddy bot- 

 toms of shallow lakes or streams. Petioles us- 

 ually slender, 2'-$' high, or when submerged 

 sometimes elongated to i or 2. Leaflets mostly 

 triangular-obovate, variable in outline, 3 // -8 // 

 long, 2 // -6 // wide, glabrous or rarely with scat- 

 tered hairs when young, the margins entire ; 

 sporocarps 2 or rarely 3 on a branching peduncle 

 which is attached to the petiole at its base, 

 covered with short yellowish-brown hairs when 

 young, becoming glabrous and dark purple 

 when mature ; sori 8 or 9 in each valve. 



Along the shores of Bantam Lake, Litchfield Co., 

 Conn., whence it has been introduced into various 

 parts of the country, notably into eastern Massachu- 

 setts. Native of Europe and Asia. 



3 



