254 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 



close clumps in an undeveloped condition. The customary thicken- 

 ing of the walls of the epidermal and other tissues did not ensue, 

 and the stele did not develop beyond a primitive stage, although the 

 etiolated leaf lived for a period of many weeks. Pleris longifolia 

 (p. 157) showed an exaggerated elongation of the entire rachis in 

 such manner that the distance between the pinnae was increased one- 

 half above that of the normal. The thickness of the rachis was 

 greater than in the normal, due to an increase in the parenchymatous 

 tissues, and the entire organ contained some chlorophyl. The pinnae 

 did not attain a size beyond one-sixth of the length of the normal, not 

 being entirely unfolded, and were held in various abnormal positions. 

 The leaves assumed an erect apogeotropic attitude, sometimes falling 

 over by their own weight. Woodwardia radicans (p. 188) produced 

 a succession of leaves after the manner of some of the seed-plants, 

 none of which developed stipes much longer than the normal. The 

 laminar rudiments remained in an unfolded condition in tightly rolled 

 clumps, the entire leaf containing some chlorophyl. 



Two species of ferns were examined in which the sporophylls 

 are specially differentiated organs, and the leaves are entirely sterile, 

 viz: Osmunda cinnamomea {^. 1 2,2) ^r\d Polys tichtim acrostichoides 

 (p. 151). Ostnunda showed an exaggerated growth of the stipe and 

 rachis. The pinnae were pinnatifid in etiolated specimens, the divi- 

 sions being fully expanded and the entire leaf was green from the 

 presence of chlorophyl. The etiolated organs were apogeotropic 

 but soon fell over by reason of their weight and great length. The 

 mechanical tissues of the epidermal region were but slightly devel- 

 oped and the steles did not advance beyond an early or incom- 

 plete stage of differentiation. The reduction was also marked in the 

 endodermal and pericyclic regions. Etiolated leaves of Polystidmm 

 underwent an exaggerated elongation of the basal portion of the 

 stipe, especially while some increase was shown by the entire rachis. 

 The pinnae remained rolled up in small clumps, being separated 

 more widely than in the normal. No development of the sporophylls 

 ensued, the stimulating action of light being apparently necessar}- to 

 start them into activity. The normal leaves of Polysiichum assume 

 a decumbent position more or less closel}'^ approaching the horizon- 

 tal, while etiolated organs are strictly erect. When etiolated leaves 

 were illuminated however, the upper portion of the rachis, bearing 

 pinnae, was brought to a position approximately horizontal by an 



