DESCRIPTION OF SPECIES— POTAME^. 99 



merits which I refer to it. The relations of the vegetable organs which have 

 been described under this generic name are uncertain; the genus itself is thus 

 temjjorarily limited. 



Caulinites spargaiiioides, Lesqz. 



Plato XIV, Figs. 4-11. 



Caulinites sparganioides, Lesqx., Annual Report, 1872, p. 391. 



Stems or rbizomas flattened by compression, cylindrical in tbe natural state, irregularly striate in 

 the length, horizontally wriukled, distantly articulate or marked across by semilunar scars, like im- 

 pressions of half -embracing leaves, and irregularly round, large warts; branches alternate, distant; 

 leaves flat, linear, veined. 



It is indeed uncertain if all the fragments figured on the plate represent 

 stems only, or if some of them are referable to rhlzomas. The largest frag- 

 ment of a stem of this species is three centimeters across. All the speci- 

 mens which we have seen, and they are very numerous, are flattened by 

 compression. They are, in tlie natural state, cylindrical, more or less inflated 

 at the nodi, semi-articulate, or cut by a deep double line surrounding the base 

 of the branches, embracing half the stems, as in figs. 4 and 10 ; they seem, 

 however, to bear traces of real articulations, indicated by scars of rootlets 

 surrounding them, as in tigs. 5 and 6. If it is the case, these fragments 

 might be considered as rhizomas and their branches, while the others (figs. 

 4, 7, 8, 10) would represent stems and branches, with sheathing-leaves under 

 them. The presence of sheaths is marked under the branch-scars by the 

 deep grooves, half embracing, in figs. 4 and 10; but one is seen also at the 

 lower end of fig. 6, which, besides, has in the middle two distinct branches 

 without appearance of sheath, and between them traces of an articulation. 

 For this reason, the relative position of all the fragments is not clear. Fig. 

 ,8, for example, has in its lower part a branch similar to an unopened bud, 

 with a round wart at its base, while the upper end shows like a bud ot 

 the same form, half sheathing or embracing, with apparently a fragment 

 of a leaf behind it. The diflerent representation of these two buds, or 

 branches, may result from their position, the one at the top being seen 

 flattened vertically, the other laterally. Fig. 7 shows the scar of a small 

 branch, underlaid by a wart, a kind of scars considered and described by 

 authors under this name, but which may be remains of abortive or adven- 

 titious rootlets. They seem to be very rare upon the parts which I 

 consider as the branch-bearing leaves of the plants, as in figs. 4 and 

 10. These stems, when in a good state of preservation, are covered l)y 



