8 



C. BULBiFERA Beenh. (B1 adder- Fern) - 10—20 inches 

 high ; frond elongate-lanceolate, twice pinnate ; pinnae numer- 

 ous, short, usually opposite; pinnules narrowly oblong, cut, 

 lobed or nearly entire ; one sorus to each lobe ; rhachis and pin- 

 nae often bearing bladder like bulbets on the under side, wing- 

 less. Common near the base of calcarious cliffs in the eastern 

 counties of Iowa. July— September. This fern varies much, 



and some of its forms closely resemble the next. 



-I 



C. FRAGiLis Bernh. Usually shorter, frond oblong, lanceo- 

 late, twice pinnate ; pinnules cut toothed or pinnatifid, about 

 one sorus to each segment ; pinnae and pinnules ovate or ovate- 

 lanceolate, decurrent. Common all over the state in wooded 

 districts. Prefers calcarious soil. July— September. 



9. ASPIDIUMSWARTZ. Shield or Wood-Fern. 



Fruit dots round, borne on the back of free veins, between the 

 midrib and margin ; indusium orbicular and attached by a de- 

 pressed center, or kidney shaped and centrally attached or at 

 the sinus, opening at the margin ; stipe continuous with the 

 rootstock, covered with chaffy scales. 



A. ACKOSTiCHOiDES SwARTZ. (Christmas-Fern). Frond 

 10 — 30 inches high, lanceolate, once pinnate, stalked ; pinnae 

 alternate, somewhat scythe-shaped, oblong-lanceolate, appressed 

 mucronate toothed, half-halberd-lobed on upper side at the base, 

 short stalked ; the fertile pinnules much contracted, terminal ; 

 fruit dots in two rows near the th« midrib, becoming contiguous; 

 indusium circular, attached by a depressed center. Evergreen 

 ferns with a chaffy rhachis. Prefers wooded cliffs. July — 

 August. Not common. Muscatine and Johnson counties. 



A. GOLDiANUM HooK, Frond about 3 feet high, broadly 

 ovate, stipe chaffy ; pinnae many, about opposite, oblong lanceo- 

 late, pinnately parted or divided ; pinnules somewhat decurrent 

 on the secondary rhachis, cleft teeth appressed ; fruit dots small, 

 near the midrib ; indusium large, orbicular. Grows usually with 

 the fronds in a tufted circle. Rich woods. July — Gct(*ber. 

 Eastern river counties. 



