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— r9r3] HOLDEN—RAY TRACHEIDS 61 
occidentalis. Figs. 12 and 13 show a characteristic region of 
T. occidentalis. The tracheids are invariably marginal, with small 
_ bordered pits communicating with the parenchymatous ray cells, 
_ and slightly larger ones on their slanting end walls. T. globosa 
and T. orientalis, as far as examined, are entirely without ray 
tracheids, while in 7. dolobrata they are rare. 
PENHALLOwW (6) has described ray tracheids in Juniperus nana, 
_ but states that they are lacking elsewhere in this genus. Wounds, 
_ however, in almost every species examined, sufficed to recall them. 
In Juniperus they occur usually as large, very irregularly shaped 
cells, thickly pitted on the tangential wall, constituting the whole 
of a ray one cell high. Rarely, also, they occur on the margin 
of parenchymatous rays, in which case the horizontal wall only is 
pitted. Fig. 14 shows a ray from J. californica. Ray tracheids 
have been observed in the following species: J. californica, J. vir- 
giniana, J. pachyploea, J. scopulorum, J. occidentalis, J. chinensis, 
J. chinensis var. alba, J. sabina, and J. barbadensis. In J. communis 
they were missing altogether from wounded seedling, stem, and root, 
| except in the wound cap of one stem which had been repeatedly 
_ injured near the ground. Three species failed to show any: J. ber- 
_ mudiana, J. californica var. utahensis, and J. macrocarpa. 
The genus Libocedrus, according to PENHALLOW, lacks ray 
| _ tracheids. Figs. 15 and 16, however, show a ray of Libocedrus 
_ decurrens with a marginal tracheid. Toward the left of fig. 15 
_ there is a bordered pit; fig. 16 shows it in greater magnification. 
_ This section was cut from wounded material, but other wounds 
examined failed to recall ray tracheids. Traumatic wood of L. 
_ chilensis and L. doneana seemed to be without them also. 
Actinostrobus and Fitsroya (F. Archeri and F. patagonica) both 
_ lack ray tracheids, as far as investigated. 
PODOCARPINEAE, TAXINEAE, AND ARAUCARINEAE 
Saxegothaea, Dacrydium, Podocarpus, Phyllocladus, Taxus, Tor- 
_-reya, Cephalotaxus, Araucaria, and Agathis were examined, but 
no ray tracheids were observed. 
