500 



ILLUSTRATIONS OF THE NATUItlx ORDEBS. 



962. Ord. Filiccs (Ferns). Leafy plants ; with the leaver (fronds) 

 spirally rolled up or circulate in vernation (except in one suborder), 

 usually rising from prostrate or subterranean rootstocks, or in tree- 

 Ferns from an erect arborescent trunk (Fig. 100), and bearing on 

 the veins of their lower surface, or along the margins, the simple 

 fructification, which consists of one-celled spore-cases (thecce or spo- 

 rangia), opening in various ways, and discharging the numerous 



minute spores. The stalk or petiole of the frond is termed a stipe. 

 — There are four principal suborders, viz.: — 



FTCJ 1287. Cnmptosorns rhizophyllus (Walking Fern); the fronds rooting, as they fre- 

 quently do, at the apex ; the sori occupying the reticulated veins on the back. 128S Division 

 (piuuula) of a frond of Aspidium Goldianum ; the roundish sori attached to the simple veins, 

 and covered with an indusium, which is fastened in the centre, and opens all around the mar- 

 gin. 1289. Magni£ed sporangium of this division of Ferns, with its stalk, and elastic ring 

 partly surrounding it ; which, tending to straighten itself when dry, tears open the sporangium, 

 shedding the minute spores (1290). 1291. Schizacapusilla of about the natural size, with simplo 

 and slender radical leaves ; the contracted fertile frond pinnate. 1292. A division (pinna) of 

 the fertile frond, m»gnified, showing the sessile sporangia occupying its lower surface. 1293. 

 Ono of the sporangia more magnified ; they have no proper ring, and open by a longitudinal 

 cleft 1294. Ophioglossum vulgatum (Adder's-tongue) ; the sporangia forming a two-ranked 

 spike on a transformed and contracted frond : a, portion of the spiko enlarged, showing the co- 

 riaceous sporangia, destitute of a ring and opeuiug transversely. 



