Johnson and Gilmore — Libocedrus and its Cone in the Irish Tertiary. 67 



We also found a fusiform sclerotic idioblast 294 x 36^. In L. salicornioides 

 from Leoben in Stygia we found an idioblast almost identical. Examination of 

 fresh material of recent species of Libocedrus showed similar sclerotic cells in 

 some of them, e.g., in L. macrolepis. Though such cells are not by any means 

 confined to Libocedrus, it is worthy of note that the fossil specimens agree with 

 one another and with the living Libocedrus species in their possession. This 

 Libocedrus-\i\.e cone is in continuity with a shoot which shows the characteristics 

 of the widely recorded fossil named L. salicornioides, specimens of which we have 

 from the same locality. 



We had already examined and identified the Interbasaltie Liboccdrns material 

 when unexpected confirmation was supplied by an interesting find in the Washing 

 Bay core (PL IV, fig. 8). The joint-like scrap 7x4 mm., represents an elongated 

 grooved internode and a node flattened out, owing probably to the insertion of 

 two opposite branches. The two lateral adpressed leaves with their decurrent 

 bases are observable. One of the short, obtuse, slightly ridged, facial leaves is 

 visible. To the left the basal joint of a lateral branch is recognizable. We have 

 introduced for comparison a scrap of Libocedrus decurrens (PI. IV, fig. 9). 

 Fortunately the fossil yielded a little tissue which on restoration (fig. 10) shows 

 an epidermis of oblong and polygonal cells with straight, simply pitted walls. 

 Stomata are in single ribands about three cells apart. Stoma and ridge 

 measure 26-36ju. 



The usually solitary nucleus-like body seen on each cell represents a papilla 

 projecting into space from the outer wall of the epidermal cell. Similar papillae 

 occur in L. decurrens, L. macrolepis. Thuja occidentalis, and Callitiis quadrividvin, 

 but not in L. plmnosa, L. Bidivilli, or Biota orient(dis. In L. chilensis and 

 Callitris robusta there are several in each cell. Berry (1) has found similar 

 papillae in Frenelopsis rctmosissima ; and Krausel (10) notes them in his lecent 

 description of the epidermis and stomata of L. salicornioides. The waviness of the wall 

 mentioned in his first account was afterwards (11) found by him to be a secondary 

 artificial feature, due to the same cause as that resulting in the spiral striation of 

 the tracheids of many Conifers, and in consequence of no systematic value. 



(Jur material is in general agreement with the Silesian material. The depression 

 of the stomata naturally lowers transpiration, and this is still further lessened by 

 the raised epidermal ring or fence which acts as a chimney or funnel. This is a 

 xerophytic feature found in a sclerophyllous flora, of which we have many 

 indications in the fossil Dicotyledonous leaves of Washing Bay still to be 

 recorded. 



We hoped that a comparison with other Conifers of the epidermis and stomata 

 of our fossil, though surface views only of it were available, would throw additional 

 light on its affinities. Hildebrand (9) found in all the many Conifers he examined 

 that the stomata are depressed below the general level of the epidermis; that the 

 shape of this depression, pit, or external chamber thus formed varied and was of 

 systematic value. In the great majority of Conifers the one or two rows or rings 

 of epidermal cells surrounding the sunk stoma have their CNternal walls at the 

 same level as the rest of the epidermis. In a few cases they have their external 

 wall below the level. This holds true for Araiicaria, Sequoia, most species of 

 Abies and Picea. A third type, foUnd more especially in the Gujjressinene, shows 

 the stoma ringed by a wall formed of the surrounding 4-6 epidermal cells raised 

 above the level of the rest of the epidermis. The wall in some cases, as in Thuja 

 plicata, is due to the papillate arched thickening of the outer wall of the cell, 

 which itself, however, is not raised above the general level. The projecting wall 



SqipNT. PROC. E.D.S., VOL. XVII, NO. 8, N 



