LYCOPODI ALES— THE GENUS LEPIDOPHLOIOS. 203 



topliloios, which, though united by many paleobotanists, have l^eeu kept 

 separate by others on the ground that the leaf scar in the latter is at the top 

 of the bolster instea^d of at the base, as in the former, are really identical, 

 since the bolsters may be inclined (and so compressed) upward, especially 

 in the smaller branches of certain species, or downward, according to the 

 species, or even to the part of the tree, the leaf being situated, morphologi- 

 cally, at the apex and always rising upward; (3) that the tuberculate 

 branches described as Halonia and regarded as a distinct genus of trees, as 

 roots or rhizomes of Lepidodendron, as branches of Ulodendron, and (espe- 

 ciall}' more recently) as branches oi Leindophloios, are unquestionably merely 

 the fructiferous branches of the last-named genus, since they have the same 

 bolsters and are found in actual union; (4) that the fruit is in the form of 

 cones, originating, whether sessile or pedicellate, from the Halonial tubercles. 



The identity oi Lepidopltloios and Halonia was independently and almost 

 simultaneonsly demonstrated by Potonie.^ The latter author also discovered, 

 while studying the organization of some dolomitized bolsters of Lepido- 

 phloios from Langendreer, that the two lateral cicatricules in the leaf scar 

 wei-e cross sections of cavernose tracts of thin- walled parenchyma. These 

 tracts pass downward within the bolster and coincide with the appendages 

 on the bolster at the base of the leaf, the walls of the bolster being very 

 much thinned at those points. There appears little room for doubting 

 Potonid's conclusions that the tracts of thin-walled parenchyma are tran- 

 spiratory ducts, while the appendages in the bolsters of Lepidodendron and 

 LepidopUoios are " transpiratory openings."^ Potoni^ follows Stur hi regard- 

 ing the vertical trace above the leaf on the bolster in the Lepidodendra as 

 the "ligular pit." 



Although the genus Lepidopliloios is relatively rare in our American 

 Coal Measures, the species described therein offer a complex of unique fea- 

 tures that promise an interesting if small field to the monographer. The 

 only species yet found in the Missouri flora that unquestionably belongs to 

 this genus is described below as L. Van Ingeni. The superficial cortical 

 features of the trunk of this tree are usually well presented in numerous 



'Die Zngehorigkeit von Halonia: Ber. d. deutsoh. bot. Gesell., 1893, vol. xi, Hft. 8, pp. 484-493, 

 pi. sxiii. 



-Anatoraie der beiden "Male" auf dem unteren Wangenpaar und der beiden Seiteunilrbschen 

 der Blattnarbe des Lepidodendreen-Blattpolsters: Ber. d. deutscb. bot. Gesell., 1893, vol. xi, Hft. 5, pp. 

 319-326 pl.xiv. 



