[MATTHEW] A REVIEW OF THE LITTLERIVER GROUP US 



It was a branching plant of rapid growth that flourished in wet 

 sand, and has been found chiefly in the lower part of the Little Eiver 

 group (Dadoxylon sandstone), but also at the top of the Cordai te shales. 



Stem, freely hraneliing, often in a distichous manner, solid near 

 the base (fistulous in the upper hranches?) irregularly and intermit- 

 tently ribbed lengthwise; branches jointed at intervals and bearing at 

 the joints one or several lohorls of long tapering rigid leaves,, usually 

 two or three times as long as the internodes. 



There is a sheath or annulus at the base of one row of the leaves. 

 Fructification unTcnoivn. 



This form differs from Asterophyllites in the presence of several 

 whorls of leaves at a node and in havinsr an annulus. From Annu- 

 laria it differs in not having the whorls of leaves flattened to the plane 

 of the stem and in the enlarged and solid nodes. From Calamités 

 in the absence of a regular ribbing on the stem and in having a solid 

 axis. From Arthrostigma in the regular and more distant nodes and 

 the absence of leaves from the internodes. The plant shows an analogy 

 to Equisetum in the possession of a sheath or annulns to the upper 

 whorl (when there is more than one whorl) this upper whorl may be 

 compared to the sheath in Equisetum. 



Eamicalamus dumosus n. sp. Plate YIII, Figs. 2, 3, 4 and 5. 



Stem. — The main stem is an inch or more in width and branches 

 freely in the loiver part; it there throws off strong branches at a wide 

 angle — branches which sometimes are as large as the main stem. The 

 opposite branches occur at nodes which are enlarged and more woody 

 than the internodes. These bear long, rigid leaves of varying density 

 and size; the stouter ones are sometimes two or three times as long 

 as the internodes ; there are som.ctimes itvo or three whorls of leaves 

 at an internode, and in such, case the upper ivhorl has an annulus or 

 membrane connecting the leaves about as wide as the diameter of the 

 stem; this membrane is continued up on the sides of the leaves so 

 that they are winged for about an inch, from the base. 



Leaves. — The principal leaves are from 3 to ^ mm. ivide at the 

 base, 10 to 20 cm. long and taper gradually to a point. The mature 

 leaf was thich and round, or channelled on the upper side; this leaf 

 when flattened had two or three irrrgulnrh/ raised intermittent longi- 

 tudinal ridges, which are wanting in the broader flattened part of the 

 leaf near the base; a mid-rih is seldom seen, though some thin, flat 

 leaves on the lower whorls of an internode may have a shining vascular 



Sec. IV., 1906. 8 



