160 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM, 
the material in their keeping which comes within the scope of this 
paper. 
The present instalment deals with the representatives of this 
group occurring in the Gulf Coastal Plain of the United States and 
the territory immediately adjacent to the northeast. 
MORPHOLOGICAL NOTES. 
In general appearance the plants of this group somewhat resemble 
small dwarfed forms of the club mosses (Lycopodium spp.). They 
are more or less cespitose in habit with erect, ascending, or repent, 
many-branched shoots covered with 6 to 18 rows of small sessile 
leaves. 
The shoots or main stems are usually 5 to 25 mm, long (much 
longer in a few species) ; the primary branches are somewhat shorter 
than the shoots, but not otherwise different; the secondary branches 
generally average half as long as the primary branches; and the 
ultimate branchlets are merely short spurs, slightly enlarged at the 
tip and only a few millimeters in length. The branching appears to 
be dichotomous, but Campbell’ states that it is really monopodial. 
The rhizophores are leafless, stemlike structures, which arise exog- 
enously from the stems and produce many capillary endogenous 
roots. They arise more numerously from the base of the shoots, but 
usually occur sparsely throughout their whole length. 
The leaves, which are all alike, are small and sessile, and are 
usually provided with a suture (groove) in a median line on the 
dorsal side, cilia on the margins (also often on the edges of the dor- 
sal suture), and a seta (awn) at the apex, although some of these 
characters are lacking in part of the species. As to length there is 
some diversity on the same plant, though other leaf characters are 
fairly constant. Descriptions of leaves throughout this paper refer 
to those of the primary shoots. The length of leaves is measured 
on the ventral side, from the point of attachment to the apex of the 
leaf proper, excluding the seta. It should be noted that cilia and 
setee are in all cases more or less deciduous. 
The spikes (fruiting branches) are terminal and usually more or 
less 4-angled. The sporophylls are similar to the ordinary leaves 
but wider and often provided with short lobes or auricles at the base. 
The measurements for sporophylls are taken from those in the mid- 
dle of the spike. 
Each sporophyll bears either a megasporangium or a micro- 
sporangium. The position of these on the spike varies somewhat. 
On the erect or ascending plants the megasporangia usually occupy 
the lower rows of sporophylls, while the microsporangia occupy the 
upper and by far the larger number of sporophylls. In the repent or 
7 Mosses and ferns 522, 1905. 
