144 Forest Club Annual 



cedrus very fine crystals have been found in the cells, while 

 other genera have crystal sand deposited in the cell-wall, and 

 still others have no crystals whatever. 



Primary bast fiber bundles are missing in Taxus, Tax- 

 odium, Cupressus, Thuja, Libocedrus, Juniperus and most 

 species of Pinus. They occur in Sequoia and Taxodium as 

 weak bundles with the form of the fibers essentially different 

 from that of the secondary bast fibers. 



Inner bark, The secondary bark of Sequoia, Taxus, Tax- 

 odium, Cupressus, Thuja, Libocedrus and Juniperus, has as a 

 common characteristic the concentric arrangement of the ele- 

 ments. Pinus, for the greater part, is characterized by the 

 want of bast fibers and a regular arrangement of the elements 

 of the soft bast. 



The bast fibers are arranged in single rows. Their radical 

 distance is three rows of cells of the soft bast in 

 Sequoia, Taxus, Taxodium, C upressus, Thuja, Libocedrus, 

 and Juniperus. In the five last mentioned genera the bast 

 fibers have greatly thickened walls and occur in tangential 

 rows in which the slightly sclerotic fibers are occasionally 

 interpolated, and these are nearly always :arranged in several 

 tangential rows. The latter is generally the case in Taxus 

 where a row of thin walled fibers occur between every two 

 rows of sclerotic fibers. In Sequoia all of the bast fibers were 

 found to be entirely sclerotic and here and there stone cells 

 occur. Pinus forms no stone cells, while in Abies, Picea and 

 Larix, sclerotic cells are present. 



If the soft bast consists of only three rows of cells which 

 are enclosed between bast fiber layers. (Sequoia, Taxus, Tax- 

 odium, Cupressus, Thuja, Libo, edrus and Juniperus) then the 

 middle row is parenchyma and the row on each side is made 

 up of sieve tubes. This periodic change in the formation of 

 the elements is demonstrated also in Pinus where several layers 

 of sieve tubes are always separated by simple and less num- 

 erous rows of parenchyma. The parenchyma cells have large 

 pits ; the sieve tubes, which have no cross-plates, are covered 

 along the whole wall with fine-pored sieve plates. 



Schizogenous resin pockets are wanting in the secondary 

 bark excepting in Thuja where they were found in the outside 

 layers. On the other hand lysigenous resin cysts are charac- 



