VASCULAR PLOWEELESS PLANTS. 87 



organs, and in sending up erect branches instead of leaves 

 from the rhizoma. Dr. Lindley has placed this family near 

 the Coniferae, in the class G-ymnosperm£e, on account of the 

 analogy subsisting between their reproductive organs and 

 those of the coniferse ; but they are so totally diflferent from 

 the coniferse in every other respect that this classification is 

 somewhat objectionable, and has not been generally adopted, 

 so that they still retain that place which Linnaeus assigned 

 them amongst cryptogamous plants. 



126. The stems of these plants are cylindrical, simple, or 

 branched, as in Equisetum sylvatioum (Pig. 36), striated 

 longitudinally, tubular, and articulated; the cavity of the 

 stem being closed at the articulations or joints, which are 

 readily separable and surrounded by a membranaceous-toothed 

 sheath s. The stems are, in this respect, somewhat analogous 

 in organization to those of the grasses which are solid at the 

 nodes (nodus, a knot), or joints, and tubular between the 

 internodes ; but they are without leaves, as we are unable to 

 consider as such the membranaceous sheaths which surround 

 their nodes n, or articulations above the vertieillate branches; 

 for the branches should be developed between the sheath and 

 the stem, if the sheath were a circle of abortive and united 

 leaves, whereas the sheath is, in reality, situated in the axilla 

 of the branches, and appears to be only the termination of the 

 external portion of the stem, the continuity of which is 

 broken by the formation of the nodes or articulations. The 

 whorls of branches at the nodes are jointed, striated, and 

 tubular, being solid and sheathed at the joints, like the stem 

 from which they spring. 



