24 MAESILEACEAE 



32. FILIX Adans. 

 Delicate rock ferns. Leaves with slender petioles and 2-4-pinnate blades. Sori 

 roundish, each borne on the back of a vein, Indusium membranous, hoodlike, 

 attached by a broad base on its inner, side and partly under the sorus, early thrust 

 back by the expanding sporanges, thus partially concealed. [Cystopteris Bernh.] 



Leaf-blades scarcely broader at the base, short pointed, without bulblets. 1. F.fragilis. 



Leaf-blades broadest at the base, long-tapering, bearing bulblets beneath. 2. F. bulbifera. 



1. Filix frigilis (L.) Underw. Leaves tufted; petioles 10-20 cm. long; blades 

 thin, oblong-lanceolate, slightly tapering below, 1-3 dm. long, 2-3-pinnatifid or -pin- 

 nate; leaflets lanceolate-ovate, irregularly pinnatifid, the bluntly or sharply toothed 

 segments decurrent along the margined rachis, without bulblets: indusia acute. 



On rocks and in moist grassy woods, Newfoundland to Alaska, south to Georgia and 

 Arizona. Almost cosmopolitan. 



2. FIlix bulbifera (L.) Underw. Leaves weak; petioles 10-15 cm. long, light- 

 colored; blades lanceolate from a broad base or frequently long-attenuate, 3-8 dm. 

 long, 2-3-pinnatifid or -pinnate; leaflets crowded, toothed or pinnatifid: rachis wing- 

 less, commonly bearing underneath, in the axils of the leaflets and segments, fleshy 

 bulblets, these early deciduous and giving rise to new plants: indusia truncate. 



On moist rocks, Quebec to Wisconsin, south to Tennessee and Arkansas. 



33. WOODSIA R. Br. 



Small or medium-sized ferns, growing in rocky places, the rootstock in dense 



tufts. Leaves often evergreen, clustered: petioles often jointed above the base and 



finally separating: blades 1-2-pinnate or S-jjinnatifid. Sori round, borne on the 



simply forked free veins. Indusia inferior, either roundish and soon cleft into 



irregular lobes, or deeply stellate, the filiform divisions partially concealed or 



inflexed over the sporanges. 



Indusium small and inconspicuous, the divisions filiform. 1. W. Ilvensis. 



Indusium ample, the divisions broad and early spreading. 2. W. obtusa. 



1. "Woodsia Ilvensis (L.) E. Br. Leaf -blades lanceolate, 10-25 cm. long, 

 glabrous above, more or less covered with rusty chaff beneath, as also the slender 

 jointed petioles; leaflets crowded, sessile, pinnately parted, the crowded segments 

 oblong, obscurely crenate : sori near the margins, confluent with age : indusium minute, 

 concealed beneath the sorus, its filiform segments inflexed over the sporanges. 



On exposed rocks, Labrador and Greenland to Minnesota, south to North Carolina and 

 Kentucky. Also in Europe and Asia. 



2. Woodsla obtusa (Spreng.) Torr. Petioles not jointed, stramineous in 



drying, 7-15 cm. long; leaf -blades broadly lanceolate, 15^0 cm. long, minutely 



glandular-pubescent, nearly 2-pinnate; leaflets apart, triangular-ovate or oblong, 



pinnately parted into obtuse crenate-dentate segments: sori nearer the margin than 



the midvein: indusia conspicuous, splitting into several broad jagged lobes. 



On rocks, Nova Scotia to Wisconsin, south to Georgia, Alabama and Texas. Also in 

 Alaska and British Columbia. 



Order 3. SALVINIALES. 



Aquatic or mud-inhabiting herbs, with horizontal or creeping stems, or float- 

 ing. Leaves various, sometimes filifonii, or blades entire, lobed or 2— 1-foliolate. 

 Spores of two kinds (microspores and megaspores), contained in sporocarps. 

 Megaspores germinating into simple prothallia which bear archegones, the micro- 

 spores forming still simpler prothallia bearing antherozoids. 



Plants rooting in the mud; leaves filiform or with 2- or 4-foliolate blades. Fam. L Mabsileaceae. 

 Plants floating: leaves with entire or 2-lobed blades. Fam. 2. Salviniaceae. 



Family 1. MAESILEACEAE R. Br. Marsilea Family. 



Perennial herbaceous plants rooting in mud, with slender rootstocks. 

 Leaves with 2- or 4-foliolate blades, or merely filiform. Asexual propagation 

 consisting of sporocarps borne on peduncles which arise from the rootstock near 



