TEMPSKYA. 155 



specimen of Protopteris Witteana already described, which has 

 its minute structure partially preserved, there is certainly a general 

 resemblance in texture and manner of preservation to Tempskya 

 Schimpert, and such adventitious roots as occur in the neighbour- 

 hood of the Protopteris petiole scars appear to agree with those 

 of Corda's species. 



The figure of a transverse section of a small root of Tempskya 

 given by Velenovsky (pi. vi. fig. 6) is rather of the nature of a 

 diagrammatic than a very accurate sketch ; it gives a very im- 

 perfect idea of the structure of the central vascular axis. He 

 also figures in the same diagrammatic fashion a section of a 

 DicJcsonia antarctica root ; here again the xylem is not shown at 

 all clearly. In the better specimens of Tempskya Schimperi which 

 I have examined, and in sections of fresh Dicksonia antarctica roots, 

 there is a very close agreement in structure ; in both there is a 

 well-marked diarc vascular bundle, and in both a strengthening 

 ring of sclerenchyma, with parenchyma on the outside. In pi. vi. 

 fig. 5 of his paper, Yelenovsky figures what he describes as the 

 main axis of a root with a horseshoe vascular bundle ; this seems 

 to me much more probably a section of a petiolar structure ; the 

 form of the vascular bundle is entirely different to that which we 

 find in the adventitious roots of such ferns as Dicksonia antarctica. 



Through the kindness of the Director of the Royal Gardens, 

 Kew, and of the Assistant-Curator, Mr. Watson, I have lately had 

 the opportunity of closely examining some specimens of Dicksonia 

 antarctica. In one case Mr. Watson had a well-grown stem, 

 twenty-five years old, taken out of the ground; we found that 

 just below the surface of the soil the basal part of the axis became 

 swollen owing to the greater number of adventitious roots which 

 clothed the lower part of the stem. The central vascular cylinder 

 was prolonged almost to the bottom of the underground mass of 

 roots, tapering towards its somewhat oblique termination. 



"We did not find any mass of roots below the surface, which 

 was without a central or excentric vascular axis for a sufficient 

 length to account for even the smaller specimens of Ttmpskya. 

 In the case of older and larger plants of Dicksonia, Mr. Watson 

 tells me that in such cultivated examples as he has noticed there is 

 usually a large ball-like mass of roots below the surface, but these 

 do not extend for more than a short distance, either vertically 

 downwards, or in an oblique direction, without any vascular 



