700 EXPLANATION OF THE PLATES. 



Tab. XIV. 



CENCHEUS. — Involucre of C. tribuloides, in flower, enlarged (1); longitudinal 

 section of the same (2); a spifcelet displayed (3): the stigmas should belong 

 to the right-hand flower: the left-hand or lower flower is only staminate. 



TRIPS ACUM. — Piece of the spike (of the natural size), pistillate below, stami- 

 nate above (1); a longitudinal section of one of the pistillate spilselets (2); 

 a pistillate spikelet with its parts displayed (3) ; a staminate (two-flowered) 

 spikelet, with its parts displayed (4). 



ERIANTHUS. — Part of the hairy inflorescence with two spikelets of E. alopecu- 

 roides, enlarged (1); one of the spikelets displayed (2). 



ANDEOPOGON. — Small portion of the spike of A. furcatus, enlarged, with one 

 fertile and awned spikelet, and one staminate and awnless spikelet (1); the 

 fertile spikelet (2); and the staminate spikelet (3) displayed. 



SORGHUM. — A fertile spikelet of S. nutans, enlarged, with a sterile pedicel on 

 each side (1) ; the spikelet displayed (2). 



Genera of Piliees or Ferns. 



Tab. Xr. 



POLYPODIUM. — Plant; piece of the frond (1): a magnified sporangium With its 

 stalk, and another bursting and discharging spores, of P. vulgare, L. 



STRUTHIOPTERIS. —Pinna of the sterile frond (1) of S. Germanica, WtUd. ; por- 

 tion of a fertile frond (2) ; a piece of one pinna cut off" to show the manner in 

 which it is rolled up (3); and a portion of the last, magnified, with one side 

 unrolled (4) ; towards the base of^the sporangia all removed, to show how the 

 fruit-dots are borne each on the middle of a vein. 



PELLiEA. — Sterile and fertile plants of P. gracilis, and a portion of the fertile 

 frond (1) enlarged, with a piece of the marginal indusium turned back to 

 display the fruit ; the sporangia are all removed from the fruit-bearing tips of 

 the two forks of the lower vein. 



Tab. XVI. 



PTEEIS. — A pinnule of P. aquilina, L. ; and a piece of one of the lobes, en- 

 larged (2), the marginal indusium rolled back on one side, displaying the 

 fruit ; the sporangia all removed from the lower part to show the receptacle 

 that bears them, viz. a cross line connecting the tips of the veins. 



ADIANTUM. — Piece of the frond of A. pedatum, L. (1); a pinnule somewhat 

 enlarged (2); and a piece of one (3) more enlarged, with the indusium of 

 one fruit-dot turned back to show the attachment of the fruit. 



GHEILANTHES. — Small plant of G. vestita (1); and a fruit-bearing pinnule, en- 

 larged (2). 



WOODWAEDIA. — Portion of the sterile (1) and of the fertile frond (2) of W. 

 angustifolia ; a piece of the latter enlarged (3); piece of the frond of W. Vir- 

 ginica (4); and part of a fruiting lobe (5), enlarged. 



Tab. XVII. 



CAMPTOSOEUS. — Plant of G. rhizophyllus, iini. ; and a portion of a frond, 



with fruit-dots, enlarged (1). 



SCOLOPENDRIUM. —Tip of a fertile, frond of S. vulgare; and (2) a piece en- 

 larged, with two fruit-dots. 



ASPLENIUM. — A pinna of A. thelypteroides, Michx. (1); and part of a lobe (2) in 

 fruit, enlarged. 



DICKSONIA. — Pinna of D. punotilobula. Hook. (1); portion of a pinnule (2), en- 

 larged; and a fruit-dot in its cup-shaped indusium (3). 



