INTERRELATIONSHIPS OF THE TAXINEAE 
Mary C. Buiiss 
(WITH PLATES I, II) 
In considering the Taxineae it is interesting to note the taxo- 
nomic position to which this subtribe has been assigned at various 
periods in the history of the classification of the conifers. ENGLER 
and PRANTL (4) in 1889 placed it at the top of the group; PEN- 
HALLOW (6) in 1907 placed it at the bottom of the group; COULTER 
and CHAMBERLAIN (1) in rgor regarded the subtribe as the most . 
primitive of the conifers and placed it at the bottom, but in 1910 (2) 
shifted its position to the top of the group as the most modern. 
These facts show clearly that the family is a difficult one to inter- 
pret, and the difficulty is due in part to the fact that the Taxineae 
combine at the same time extreme simplification and specialization. 
The argument presented by PENHALLOW as evidence for his 
theory that the Taxineae are the most primitive of the conifers is 
based on the progressive development of the resin canals in Pinus 
and Picea from the isolated resin cells of Podocarpus “by various 
phases of aggregation.” In Taxus and Torreya of the Taxineae, 
which he investigated, PENHALLOW states that resin cells are 
entirely wanting. Isolated resin cells occur in abundance in 
Podocarpus of the Taxineae. In the true Coniferae isolated or 
aggregated resin cells are characteristic of all the genera except 
Picea and Pinus, where they are replaced by resin passages, of which 
the aggregations of resin cells form an essential part. From the 
genera Taxus and Torreya, characterized by the absence of resin 
cells, PENHALLOW traces a series through Podocarpus, where resin 
cells are scattered, to genera of the Coniferae, where first, as in 
Taxodium and Libocedrus, the resin cells are arranged in well 
defined zones as well as scattered, to resin sacs in Abies and Sequoia, 
to resin passages with constrictions in the canal in Larix, Pseudo- 
tsuga, and Picea, to the resin passages without constrictions, as in 
inus. 
Botanical Gazette, vol. 66] [54 
