INTRODUCTION TO CRYPTOGAMIC BOTANY. 

 h 



Fig. 5. 



a Threads from peridium oi Batarrea phalloides, P. magnified, 



b A portion more liigUy magnified. 



Threads from capillitum of Podaxon carcinomalis* 



that vascular tissue is but seldom found in the young plant 

 before germination. -f 



5. A second character, distinctive of Cryptogam.s, consists 

 in the fact that gTowth takes place in these plants from the 

 tips of the threads of which they are composed and of their 

 ramifications; or in other words, that the development is 

 superficial. This, however, must be taken with much latitude, 

 for when we come to particulars, the exceptions are very 

 numerous. The rule, of course, applies to their vegetative 



* The threads of P. carcinomalis are rather allied to woody than to 

 vascular tissue. They, in fact, resemble closely the elongated cells in 

 the dark portion of the concentric rings of White Spruce "Wood from the 

 Arctic Eegions, as observed lately by Dr. Hooker. A similar structure 

 exists, in what I take to be Scotch Fir, in a piece of drift wood, picked 

 up at Lake Laura, on the western side of Wellington Channel, and 

 kindly communicated to me by Capt. Inglefield. It is now a well-ascer- 

 tained fact that a spiral structure exists in some varieties of cellular 

 tissues, and perhaps in all. Crflger's papers in the Botanische Zeitung, 

 1854, and Agardh'' on the spiral structure in the cells of Algee, may be 

 consulted on this point. Hastig figures this spiral pleurenohyme under 

 Pinus pumilio. 



t A ready example to the contrary may be found in the fruit of the 

 Horse Chesnut. 



^ De cellulft vegetabili fibrillis tenuissimis contexts. Lundee 1 852, 



