228 THE POTOMAC OR YOUNGER MESOZOIC FLORA. 



Leptostrobus longifolius, sp. nov. 



Plate CI, Figs. 2, 3; Plate CII, Figs. 1-4; Plate CIII, Figs. 6-12; Plate CIV, Fig. 6." 



Trees or §hrubs with stout and long primary leafy branches, which 

 contain the leaves attached singly and scattered along the stem, as now 

 seen attached to the under surface or to the sides of the stems, but most 

 probably originally found spirally arranged and attached to the stems on 

 all sides. The primary leafy branches have lateral and terminal short shoots, 

 on the ends of which the leaves are arranged in tufts; leaves very long 

 and narrowly linear or needle-shaped, with their extremities in no case 

 seen, attached by the entire bases, not narrowed; nerves several, parallel, 

 slender, and obscure. 



Localities: Fishing hut above Dutch Gap Canal; Fredericksburg; 

 72d mile-post and bank near Brooke; hill-side near Potomac Run. 



The plant is not uncommon at any of the localities. It is most abun- 

 dant at the fishing hut above Dutch Gap Canal, where all the forms 

 depicted on PI. CII occur. The leaves occur, as elsewhere, most com- 

 monly detached. They seem to be quite deciduous, especially on the 

 older and larger stems. All the specimens found have suffered from mac- 

 eration and transportation in water, and hence the present mode of arrange- 

 ment of the leaves in the comparatively few cases where they are found 

 attached does not give an accurate picture of their original condition. 

 The leaves in tufts at the ends of the short shoots may represent all that 

 were originally present, or they may be only the younger last-formed ones, 

 the older ones lower on the twigs having fallen off. 



This latter is probably the true state of the case. At any rate, these 

 short shoots seem to be growths from lateral buds, perhaps annually formed. 

 Neither on these nor on the longer main stems are any scars left by fallen 

 leaves to be seen, but this does not prove that they were not present, for 

 in all cases the naked portions have lost their epidermis and suffered a 

 good deal fi'om maceration. They are decorticated and reduced to the 

 woody fiber, or show only imprints of this. The leaves as now seen on the 

 older and larger stems seem to be all attached laterally, or to the ends of 

 the stems or to the under surface. This is probably due to the accidents 



