POLYPODIACEAE 23 



28. MATTEUCCIA Todaro. 



Coarse lowland ferns with free-veined dimorphous leaves. Sterile leaves tall, in 

 a complete circle, the shorter fertile ones borne within, rigidly erect, with leaflets 

 closely contracted into necklace-like or pod-like divisions, these, as in Onoclea, com- 

 pletely concealing the sori, finally dehiscent. Sori roundish, on elevated receptacles, 

 partly covered by delicate lacerate indusia attached below. 



1. Matteuccia Struthldpteris (L.) Todaro. Bootstock ascending, emitting 

 slender stolons. Fertile leaves 3-5 dm. high, the divisions dark brown, slightly 

 crenate, contracted, with widely revolute margins, the included sori crowded and 

 confluent. Sterile leaves 6-18 dm. long, 1.5-3.5 dm. broad, broadly oblanceolate, 

 abruptly short -acuminate, gradually narrowed below the middle, the lower leaflets 

 greatly reduced; leaflets narrow, deeply pinnatifid, glabrous, the segments oblong, 

 obtuse, entire. {Onoclea Struthiopteris (L.) Hoffm.] 



In moist thickets, especially on river banks, Nova Scotia to British Columbia, south to 

 Virginia and Arkansas. Ostrich Fern. 



29. NEPHROLEPIS Schott. 



Terrestrial or epiphytic mainly tropical plants. Leaves spreading or pendent: 

 blades elongated: leaflets numerous, approximate, articulate. Sori roundish, rising 

 from the apex of the upper branch of a vein, usually near the margin. Veins free. 



Leaf-blades 7-15 cm. wide: indusia distinctly reniform. 1. A^. exaltata. 



Leaf-blades 20-30 cm. wide: indusia nearly orbicular. 2. N. biserrata. 



1. Nephrolepis exaltata (L.) Schott. Petioles 10-15 cm. long; leaf -blades 

 3-20 dm, long, 7-15 cm. wide; leaflets lanceolate to oblong, sometimes crenulate, 

 auricled at the base above, rounded below: indusia reniform. 



On logs and stumps, peninsular Florida. Also in the tropics. Sword or Boston Fern. 



2. Nephrolepis biserrata (Sw.) Schott. Petioles 10-50 cm. long; leaf-blades 

 6-30 dm. long, 20-40 cm. wide; leaflets 10-20 cm. long, acute, entire or crenulate, the 

 auricled at the base above, rounded below: indusia nearly orbicular. [N. acuta Presl.] 



In hammocks, southern peninsular Florida. Also in tropical regions. 



30. SPHENOMERIS Maxon. 



Mainly tropical ferns, with slender creeping hairy rootstocks and subfasciculate 

 ascending or drooping leaves of medium size. Petioles not jointed to the rootstock: 

 blades very obliquely 3^-pinnate or -pinnatifid, the divisions alternate, the ultimate 

 ones cuneate, with free veins. Sori terminal at or near the truncate apex of the 

 segments, single or 2-4 joined. Indusium flattish, pocket-like, similar to the opposed 

 leaf-margin, attached at the base and sides, open toward the apex of the segment. 



1. Sphenomeris clavata (L.) Maxon. Leaves numerous, close ; petioles slender, 

 stramineous, naked, 1-2.5 dm. long; blades deltoid-ovate to linear-oblong, 1-3.5 dm. 

 long, 3-4-pinnate, light green, the leaflets stalked, the rachises slender and flexuous; 

 ultimate segments linear-cuneate, simple or cleft, each with 1 or 2 simple or forked 

 veins, the apex toothed: indusia single at the clavate ends of the veins, or if joined 

 borne upon a translucent veinlet connecting these. [Odontosoria clavata (L.) J. Sm.] 



In moist limestone sinks, southern peninsular Florida. Also in the West Indies. 



31. DENNSTAEDTIA Bernh. 



Medium sized ferns with slender wide-creeping hairy rootstocks and scattered 



2-3-pinnate erect leaves. Sori marginal, terminal upon the free veinlets, the 



sporanges clustered upon a small receptacle within a special cup-shaped indusium 



formed in part of the more or less modified reflexed segment of the leaf -margin. 



1. Dennstaedtia punctilobula (Michx.) Moore. Petioles stout, chaflSess, pale 

 green; leaf -blades 3-10 dm. long, lanceolate to deltoid-lanceolate, acute to long- 

 attenuate, usually 3-pinnatifid, thin and delicate; rachis and under surface minutely 

 glandular and pubescent; leaflets numerous, lanceolate; segments close, ovate to 

 oblong, deeply lobed, the margins with oblique rounded teeth: sori minute, each on a 

 recurved toothlet, usually one at the upper margin of each lobe. [DicTcsonia puncti- 

 lobula (Michx.) A. Gray.] 



On open hillsides. New Brimswick to Ontario and Minnesota, south to Georgia and 

 Alabama. 



