210 



DE. AGNES AEBER ON THE 



In this case the sterile upgrowth {st.p.) is usually well preserved and can be seen to 

 consist of delicate cellular tissue. The sterile plate is still better displayed in certain 

 sections of sporangia near the apex of a cone of L. oldhamius which occur in a 

 preparation in the University College Collection * (PI. 24. fig. 17). The most remarkable 

 instances of sterile plates with which I am acquainted, however, are to be found in a 

 series of obliquely transverse sections of a cone from Shore, Littleborough, preserved 

 in the Leiden Herbarium (Slides 211-214). A single section, which obviously, from 

 internal evidence, belongs to the same seri'es and must have been cut from this identical 

 cone, has been presented by Miss Winifred Smith to the Sedgwick Museum, Cambridge f. 

 From a study of the latter section alone, I originally drew the conclusion that this 

 cone represented a new species, to which, in a preliminary note %, I gave the name 

 Zepidostrohtis laminutus. An examination of the Leiden slides, which I have recently 

 had the opportunity of making, through the kindness of Dr. Jongmans, has convinced 

 me that the cone in question is not specifically different from L. oldhamius ; the name 

 L. laminatus must hence be discarded. The sections of the cone are useful because 

 they pass obliquely through the apex: and display the internal structure of immature 

 sporangia with great clearness. The sterile plates in these young spore-sacs are massive 

 and well preserved, and give rise with great regularity to two smaller lateral processes, 

 one on either side {stp., PL 21. figs. 1 & 3 and Pi. 24. figs. 15 & 16). The branches are not 

 directly opposite to one another, and the main process is continued above its branches 

 for a considerable distance. That these outcrrovvths are of the nature of plates, ruunii 



OP 



in the direction of the long axis of the sporangium, and are not merely peg-like 

 structures, is evidenced by the fact that they present a general similarity of appearance 

 in the seven sporangia in which they are visible in the section represented in PL 21. fig. L 



These sporangia, owing to the fortunate obliquity of the section, are cut at varymg 

 distances from the main axis, and we are hence enabled to visualise the structure ot 

 a complete individual sporangium. Another point, which is established by the comparison 

 of the different sporangia, is that the sterile plate died out towards the distal end of the 

 spore-sac- The lowest sporangium figured in PL 24. fig. 15, which is also shown photo- 

 graphically in PL 21. fig. 2, is obviously cut through near the distal end, since the ligule 



[Ig) is visible. In this case there is no sterile upgrowth from the " sub-arch esporial 

 pad" 6. The structure of one of the sterile processes is shown in detail in PL 24. fig. 16 



In the older sporangia the sterile plates are relatively less important ; the lateral branch 

 plates seem to shrivel and disappear quite early. 



The type section oi Lepidostrohus foliaceus, Maslen (Williamson Coll., C.N. 1614), i! 

 approximately radial, but more or less tangential in the middle region. In at least tw( 

 sporangia there are indications of a sterile plate si^^il^^ to ^^^ 3^^* described u 



« 



U.C.L. Coll., C. 19. 



t Slide 2S1, Sedgwick Muaciim Coll. This section probably belongs between Slides 213 and 214 of the Leiden 

 Herbarium GoU. 



Arber, A. ('13). § Eowcr, F. 0. ('94), p. 513. 



