A) pycnoxylic only
B) polyxylic only
C) manoxylic and diploxylic
D) none of the above
Correct Answer: C
Solution :
The cambium ring in Cycas stem produces secondary xylem towards inner side and secondary phloem towards outer side. In this way successive zones of secondary xylem and phloem alternating with parenchymatous tissue are formed. This type of condition is called polyxylic condition. As the large amount of parenchymatous cells are interspersed with the secondary xylem tracheids, wood is called soft-wood (manoxylic wood). In Pinus the secondary wood show well marked growth rings which are formed annually. Each annual ring possess a zone of spring wood and autumn wood. The wood consists of tracheids traversed by rays, and is dense and massive (i.e., pycnoxylic).
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