450 MR WM. T. GORDON 



arises from the base of this pit. It is tongue-shaped, and consists of uniform small- 

 celled parenchyma. It does not quite fill the pit (figs. 10 and 14, lg.). 



The top of the ligule pit communicates with the exterior by a short, straight canal, 

 surrounded in places, especially near its base, by the same pallisade tissue which lines 

 the ligule pit. This canal (fig. 10, lg. c.) opens far back from the leaf-scar into the space 

 between the leaf-base and the next overlying one. In this way the opening is protected 

 from injury and is not exposed on the outside of the plant. In all the other examples 

 of Lepidophloios I have seen this canal opens near the leaf-scar and on the exposed 

 portion of the leaf-base. The canal is oval in section, being broader than high, and the 

 opening at the top is triangular, with the base of the triangle towards the axis of the 

 stem. 



As mentioned before, a strand of parichnos underlies the leaf-trace for the greater 

 part of its length in the outer cortex and leaf-base. This strand is of very loosely 

 packed, thin-walled cells ; it divides into two in the leaf-base, and, rising to the level of 

 the bundle, these two branches pass out at the leaf-scar, one on each side of the bundle. 

 As the tissue of the parichnos is well preserved, I have been able to follow its 

 course by both longitudinal and transverse sections. In the inner part of the 

 periderm no parichnos can be distinguished, nor in any case has it been seen further in 

 than the periderm. Fig. 11 shows the bundle v.b., and on the upper side there is 

 parenchyma. This section is cut near a branch, so that the traces can be seen both in 

 the periderm and in the inner part of the outer cortex. Those in the periderm have 

 the parichnos on the opposite side of the trace from that of fig. 1 1. The parenchyma 

 above this trace belongs to the middle cortex. Passing into the periderm the paren- 

 chyma above the bundle gets less, but, a little way in, a distinct elongated portion 

 below the bundle becomes visible (fig. 12, 2 par.), and this I take to be the true parichnos. 

 As the exterior is approached this tissue increases in amount, until, just outside the peri- 

 derm, it occupies the lower two-thirds of the leaf- trace (fig. 12, 1 par. and 3 par. ; 

 fig. 13, par.). The parichnos then communicates with the inside of the stem through the 

 parenchymatous bundle sheath and not directly. 



On entering the leaf-base the parichnos is still long and narrow, but quickly shortens 

 and broadens into the typical kidney-shaped strand. Fig. 12 shows three leaf-traces; 

 of these, two (Nos. 1 and 3) are near the outside of the periderm and just going to pass 

 into the leaf-base, the third (No. 2) is further into the stem ; the increase in the parich- 

 nos is well seen in these three traces. 



In the leaf-base this strand can be traced quite a long distance before it forks 

 (fig. 14, par.) ; the forking takes place just beyond a plane drawn through the opening 

 of the ligule canal and parallel to the main axis. Sections which show any portion of 

 either ligule or ligule canal invariably also show a single parichnos strand. Such a 

 long stretch of unbranched parichnos is unusual. Fig. 9 shows a leaf-base beyond 

 the region where the single strand is got, so the parichnos is represented by two masses 

 of tissue, one on each side of the leaf-trace (fig. 9, par., par.). 



