322 ANNUAL REPORT SMITHSONIAN INSTITUTION, 19 2 8 



The fronds of the Gilboa tree are compound, tripinnate (three 

 divisions), and, judging from the fragments and larger specimens 

 collected, were at least 6 to 9 feet long, (See pi. 8, figs. 1 and 2.) 

 The pinnules were bilobed, with the lobes slightly recurved. The im- 

 pression of the main rachis or stem of the frond in the widest part 

 varies from three-eighths to five-eighths inch in the larger speci- 

 mens. Both the primary and secondary divisions are alternately ar- 

 ranged. The petioles are described as slender and much expanded 

 at the base and spirally arranged in about five ranks. Specimens of 

 outer bark showing petiolar scars were collected in the summer of 

 1925, but as yet the museum has not located any specimens of trunks 

 showing the attachment of the petioles. About 1870 or 1871 a Mr. 

 Lockwood, of Gilboa, found the upper part of one of these trunks 

 with its leaf scars preserved and petioles attached. The specimen 

 was described by Sir William Dawson as probably the upper part of 

 one or the other of his species of Psaronius found in the same bed. 



The seeds of this Upper Devonian tree (see pi, 9) bear a strong ex- 

 ternal resemblance to those of the Carboniferous seed fern Lyginop- 

 teris oldhamia and to other Lyginopterid seeds. They were borne 

 in pairs at the end of forked branchlets and were probably borne near 

 the tip of the frond. Sometimes the dichotomies are such a short dis- 

 tance apart as to bring frequently two, sometimes three, pairs of 

 seeds close together, giving a clustered effect to the seeds. The seed 

 is broadly oval (measuring in the larger specimens 5.3 by 2,5 milli- 

 meters to 6.4 by 3,4 millimeters) and inclosed in an outer husk or 

 cupule, which in some cases appears to be lobed. Separate nutlets 

 were found. They occur in groups of small, rounded, thick bodies. 



The second type of fruiting body found has been interpreted to be 

 part of the male fructification, a sporangia-bearing organ (sporan- 

 giophore), though no separate sporangia have been found. These 

 sporangia-bearing organs are modified pinnules; they are rounded- 

 oval, saucer-shaped to funnel-shaped, and are borne on branching 

 pedicels. It is believed that the sporangia were clustered and at- 

 tached to the underside of the sporangiophore near the place of 

 attachment of the pedicel and extending out toward the margin. 



The two species described by Dawson were distinguished by the 

 arrangement of the sclerenchyma strands of the outer cortex, which 

 he interpreted as aerial roots ; and to-day the species can stand only 

 on those characters upon which they were originally separated, since 

 we have discovered nothing further to add. His " Psaronius " tex- 

 tilis (pi, 5, fig, 1) is distinguished by a network of interlacing strands 

 of sclerenchyma and ''''Psaronius'''' erianus (pi, 5, fig, 2) by more or 

 less parallel strands. Only one kind of foliage has been found ; also 

 only one type of seed and male fructification. It would appear, then, 

 that only in the internal structure of the trunks could these two 



