EXPLANATION OF PLATE XXL 



EQriSETU.^L— (1) Upper part of fertile plant of E. liinosnm ; (2) one of 

 the shield shaped scales or receptacles of the spike, with the six sporangia 

 nnderneath, enlarged ; (3) same seen from below, discharging the spores ; 



(4) a magnified spore with the clnh-shaped filaments s])reading; and 



(5) the same with the filaments coiled up. 



LYCOPODIUM.— riant of L. Caroliniannm, and (1) a magnifieil scale of 

 the spike removed, with the sporangium in its axil, discharging powdery 

 spores. 



SELAGINELL A. — Plant of S. rupestris ; ( 1 ) i)art of a fertile spike, enlarged ; 

 (2) scale from the upper part of it, with its sporangium, containfng innu- 

 merable powdery spores ; (3) scale from the base, with its sporangium 

 containing feAv large spores; and (4) three large spores. 



LSOETES. — (1) Plant of L lacustris; (2) sporocarp containing the minute 

 spores, cut across, enlarged; (.5) same divided lengthwise; (3) sporocarp 

 with the large spores, divided lengtliwise; and (4) tliree large spores 

 more magnified. 



AZOLLA. — (1) I'lant; (2) a jiortion magnified, with conceptacles of both 

 kinds; (3) the macrosporic one, more magnified; (4) the microsporic 

 one, more magnified ; (5) the same burst open, showing the stalked micro- 

 sj)orangia; (6) one of the latter more magnified; (7) another bursting; 

 and (8) three masses of microspores beset with glochidiate or barbed 

 bristles. 



