Flora of the Palouse Region 



8. PHEGOPTERIS. 



Medium sized or small ferns: leaves 2-3-pinnate or ternate; 

 leaf-stalk not articulated with the rootstock; fertile and sterile 

 leaves similar (in ours): sori small, round, borne on the backs of 

 veins below their ends; indusium none. 



P. dryopteris Fee. Rootstock slender, horizontally creeping: petioles 

 15-20 cm. tall, pale straw-color, shiny, bearing a few brownish scales toward 

 the base; blades broadly triangular in outline, 10-20 cm. wide, ternate, the 

 lateral primary divisions bipinnate, tbe terminal usually tripinnatejall naked 

 at the base; pinnae oblong, 2-5 cm. long, glabrous, pinnately cleft or divided 

 into 15-25 obtuse lobes: sori near the margin, on the ends of free veins. 

 Common in rich woods, Thatuna Hills. 



Order 4. HYDROPTERIDEAE. 



Plant perennial, herbaceous, rooting in the mud, with slender 

 creeping rootstock and 4-foliolate or filiform leaves: sporangia 

 borne within closed receptacles (the sporocarps) which arise from 

 the rootstock near the leafstalks or are consolidated with them; 

 spores of two kinds, macrospores and microspores, both contained 

 in the same sporocarp. 



Family 4. MARSILIACEAE. 



Characters of the Order. 



9. MARSILIA. 



Marsh or aquatic plants: leaves slender-petioled, quadrifoliolate, 

 commonly floating on the surface of shallow water: sporocarps 

 ovoid or beau-shaped, peduncled and rising from the petiole or 

 from the rootstock at the base of the petiole, composed of two ver- 

 tical valves having several transverse compartments (sori) in each 

 valve; also provided inside with a ring which at the opening of 

 the valves swells and tears the sori from their positions: sori com- 

 posed of both macrosporangia and microsporangia. 



M. vestita Hook & Grew Rootstock slender, creeping: leaves more or 

 less pubescent with white hairs; petioles slender, 4-12 cm. long; leaflets 

 deltoid-obovate, 4-12 mm. long, mostly entire: sporocarps solitary on the 

 stalks, 4-8 mm. long, 3-5 mm. wide, with a short raphe, a short blunt lower 

 tooth, and an acute upper one, densely pubescent with white appressed hair- 

 like scales: sori 6-1 1 in each valve. 



Common on the banks of streams in spring and early summer, frequently 

 aquatic, the leaves floating on the surface. 



Class 2. EQUISETINEAE. 



Plant rush-like with hollow jointed stems rising from 

 subterranean rootstocks: sterile leaves reduced to minute scales, 

 whorled, forming sheaths at the joints; fertile leaves forming a 

 short spike terminating the stem: epidermis rough. 



