310 



MISS I. B. J. SOLLA.S OX THE STRUCTtTEE AND [Aug. I9OI, 



Confining our attention to such a 

 stem, one sees first the epidermis 

 composed of long rectangular cells. 

 A few strokes of the hone sufiice to 

 remove this layer, exposing to view 

 a number of thin-walled tubes of 

 rather wide lumen running longitu- 

 dinally in the stem (fig. 3). They 

 lie for the most part parallel one to 

 the other, but are often frayed out at 

 the broken ends of the stem ,• and 

 in a few cases I have seen a single 

 one of them passing into the base 

 of a leaf. No scalariform markings, 

 or indeed regular markings of any 

 kind, occur on the walls of these 

 tubes, which appear to be mere films 

 of granules of iron-oxide of various 

 sizes. Among these wide tubes are 

 occasionally fine threads of iron- 

 oxide, which, if they may be assumed 

 to be casts, bear witness to the 

 existence of vessels of a narrower 

 lumen also. When by farther grind- 

 ing the vessels are removed, the 

 epidermis of tbe other side of the 

 stem alone remains. 



The leaves, when seen in vertical 

 section, show only a single layer of 

 complete cells ; while irregular re- 

 mains of cell-walls are attached to 

 the morphologically lower surface of 

 this layer. 



The nature of the sporangia, their 

 position at the bases of leaves, and 

 the characters of the spores, all 

 suggest that liaiadita would he more 

 naturally associated with Lycopo- 

 diales than with the Musci. Vege- 

 tative characters are generally re- 

 cognized as of little value in dis- 

 tinguishing these groups ; but I 

 think that such evidence as is afforded 

 by them is at any rate not conflicting 

 with that furnished by the repro- 

 ductive organs. 



The absence of stomata in a plant, 

 which we propose to regard as of 

 sporophytic nature, calls for con- 



Fig. 3. — Sic etch based on a 

 camera-luoida drawing of 

 a section of a stem of 'N. lan- 

 ceolata. ( x 18). 



< 



I. 



a = Base of a leaf 

 attached to the 

 stem. 



b = Thread of iron- 

 oxide, presum- 

 ably tilling the 

 lumen of a tube. 



c=Thin- walled 

 tubes. 



