THE 
MONTHLY MICROSCOPICAL JOURNAL. 
NOYEMBEE 1, 1869. 
I. — On the Structure of the 8te?ns of the Arborescent Lycopo- 
diacese of the Coal-Measures (Ulodendron minus, Lindl. and 
Hutt). By Wm. Carruthers, F.L.S., F.G.S., Botanical Depart- 
ment, British Museum. 
Plate XXXI. 
The genus Ulodendron was established by Lindley in the " Fossil 
Flora " for a group of Lepidodendroid stems, which, besides the 
rhomboidal leaf scars arranged spirally on the stem as in Lepido- 
dendron, had deep oval or circular cavities ranged in two vertical 
rows on opposite sides of the trunk. Several species have been 
recorded, all of them from the Coal-measures. Professor Morris, 
in the last edition of his Catalogue of British Fossils, gives the 
names of seven species ; but some of these must be reduced to 
synonyms. Belonging to the same group are two other forms 
which have received generic designations, but which should be 
placed, I believe, in this genus. These are Megaphyton and 
Bothrodendron : the only character which distinguishes the latter 
genus from Ulodendron is the obliquely oval form of the vertical 
scars. Megaphyton is based upon amorphous casts of a portion of 
the interior of the stem of Ulodendron. The series of scars repre- 
sent the cavities, through which the vascular bundles to the vertical 
appendages passed, as they existed on the inner surface of the 
EXPLANATION OF PLATE XXXI. 
Fig. 1. — Transverse section of a little more tlian half of the flattened stem of 
Ulodendron minus, Lindl. and Hutt., showing tlie scalariform axis — 
natural size. 
„ 2. — Transverse section of a portion of the axis. a. the large irregularly- 
arranged scalariform vessels of the intciior. h. the smaller radiating 
scalariform vessels of the investing cylinder. The tissues have beoi 
destroyed in the light-coloured portions, and the space filled in with 
carbonate of lime. 
„ 3. — Longitudinal section of the same, lettered as in Fig. 2. 
„ 4. — Longitudinal tangential section, showing the openings between the vas- 
cular bundles. 
VOL. II. 
