HoLLOWAT. — Studies in the New Zealand Species of Lyoopodiuni. 197 



Fig. 15. — Lycopodium jastigiatum. Trans- 

 verse section of portion of stele of 

 main rhizome. x 137. 



for the different staining-qualities of these two zones is not clear. The 

 cortex consists of an inner, narrow, very strongly sclerenchymatous region 

 of exactly the same nature as in 

 the rhizome of L. densmn, and a 

 broad median zone of much less 

 thickened cells which are abund- 

 antly stored with starch. The 

 outer region of the cortex in this 

 species is peculiar. There is a layer 

 of small-celled comi:)act paren- 

 chyma, three to four cells in width, 

 and bounded externally by a 

 strongly cuticularized epidermis 

 which is wholly without stomata, 

 and this is separated from the 

 median rather thick-walled cortical 

 region by a layer of enormously 

 large thin- walled empty paren- 

 chyma cells, two or three cells in 

 width. It is rather difficult to say 

 what is the significance of this 

 peculiar wide-celled zone. Possibly it functions as a water-storing tissue. 

 If the rhizome had been epigaeous it might have been interpreted as an 

 aeration tissue. The outermost cortical zone easily tears away in this 

 region, and in dried herbarium specimens of the Browning Pass form 

 I have also noticed the same. 



The main stems of L. scariosum are stout and epigaeous. and not very 

 widely spreading. In point of actual size the stele is not much larger than 

 that of L. volubde, but it contains twice the amount of vascular tissue, owing 

 to the fact that the xylem and phloem elements are all very much smaller 

 in size than in the latter species. This will be at once apparent from 



fig. 16, which should be com- 

 pared with that illustrating 

 the stele of L. voluhile. In 

 L. scariosum there is also an 

 entire absence of the small 

 tracheides flanking the large 

 metaxylem elements, which 

 present so characteristic a 

 feature in the stele of L. 

 voluhile, and to a smaller 

 extent also in that of the other 

 two species. The number of 

 protoxyleni groups in the full- 

 grown stem of L. voluhile is 

 from ten to sixteen, but in 

 that of L. scariosum it is 

 from eighteen to twenty-seven. 

 The stout size of the rhizome is due to the very large cortex, which 

 consists of an almost uniform tissue of not very strongly thickened 

 sclerenchyma. There is no inner strongly sclerenchymatous zone such 

 as exists in the other three species. I did not observe starch in the 

 cortical tissues, although this may possibly be present at certain seasons 



Fig. 



16. — Lycopodium scariosum. Transverse 

 section of portion of stele of main 

 stem. X 137. 



