REPORT OF THE DIRECTOR, 1922 : 53 
found in Schoharie county (Gilboa) ; and both species, in fact, are 
being obtained today from this area. The name Psaronius was 
inappropriately used for these trees, and indeed they belong to an 
entirely different group. The structure of Psaronius has been 
worked out in a most elaborate manner. This genus contains a 
large number of species from the Permo-carboniferous strata, all of 
which agree in having a highly complex polystelic organization, com- 
parable to that of the most highly differentiated fern stems of the 
Bresent eGayan el Sali O nis pymtoerenore sy iS) ay thuen) Lenn OF, 
Pteridophyte. 
Even when it was definitely known that these trees did not belong 
with Psaronius, the problem of their relationship still remained, 
though it was recognized that the cortical structure bore a resem- 
blance to that of Lyginodendron. The name Lyginodendron’ 
was first given to a specimen that had nothing to do with the plant 
usually known as Lyginodendron oldhamium, described 
by Binney? as Dadoxylon oldhamium and placed in the 
genus Lyginodendron by Williamson.? This plant later was 
found to be a Pteridosperm and Potonié in 18991° proposed for it the 
now accepted name of Lyginopteris oldhamia. Gourlie’s 
type specimen, Lyginodendron landsburgii, came from 
the Carboniferous rock of Ayrshire, Scotland and is the cast of a 
plant having in the outer cortex an irregular, anastomosing mechan- 
ical system of sclerenchyma plates. Potonié? proposed that the 
name Lyginodendron would serve a useful purpose for casts of 
stems similar to Gourlie’s type but which can not be assigned to a 
definite systematic position. The largest example (100 cm long) 
of this Lyginodendron structure was noted by Seward’? in a cast 
from the Upper Carboniferous near Harrogate. Nathorst?® recently 
figured a similar cast from Spitzbergen, from the Culm, and has 
also described under the name of Lyginodendron sver- 
*Corda, Gdoppert, .Stenzel, Solms-Laubach, etc. in Germany; Zeiller, 
Renault, Pelourde, etc. in France (see Scott, D. H., Studies in Fossil 
Botany, pt 1, 3d. ed.,; 1920, p. 270-78). 
Derby, Orville A., Observations on the Stem Structure of Psaronius 
aaiansiinliiie 1s)11s). Amer. Jour. Sci., ser. 4, 1914, 63 :480-97. 
"Gourlie, W., Proc. Phil. Soc. Glasgow, 1844, I :105. 
*Proc. Lit. Phil. Soc. Manchester, 1866, 5:113. 
mahiiedransy Rov, SOC. 1673, 163. :404. 
® Lehrbuch der Pflanzenpalaeontologie, Deelzale 
™ Ref. cited. 
~ Seward, A. C., Fossil Plants, 1917, 3:3 
i Nathorst, EN ieh Zur Fossilen Flora ae Polarlander. Teil 1, 
Nachtrage zur Palaozoischen Flora Spitzbergens, pl. 7, fig. 1. Stockholm 
1914. 
