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IOWA ACADEMY OF SCIENCE Vol. XXIX, 1922 
Cult, frequent. 
Campus ; East city line. 
B. C. to Mex. from Rocky Mts. to coast. 
FI. April. Fr. Oct. 
Note: The Douglas fir is the most majestic tree of the northwestern 
forests, towering to 70m. in height, averaging 2m. in diameter, and often 
attaining a diameter of 3 m. The timber is hard and of great value. In 
this region it is a handsome tree, but loses its lower branches rather early. 
7. Taxodium Bald Cypress Southern Cypress 
(Taxus, yew-tree; eidos, resemblance. The foliage resembles that of the yew- 
tree) 
Conical tree with stringy bark. Lvs. spirally arranged but 
spreading out in 2 rows, light green, 15mm. long, 1-2 mm. wide. 
Leaf-bearing twigs fall off in autumn with the lvs. 
Cones spherical, rough, Stam. fl. in branching spikes, the scales 
bearing 2-5 sporangia. 
1. T. distichum Two-rowed T. 
Characters of the genus. 
Cult, very rare. 
Campus. 
Del. to s. 111., Mo., Fla., and Tex. 
Fl. May. Fr. 
Note: One specimen of this tree prospers on the Grinnell College cam- 
pus. It is native of swamps, often in deep water, in the southern states. 
There it grows to a great diameter, and sends up huge woody breathing 
roots called cypress or cedar “knees,” often 2 m. high and 3 dm. thick. 
The cypress lumber now so much used comes from this tree, but not the 
so-called cypress shingles. Shingles are made from Chamaecyparis thyoides 
in the east, and from Thuja plicata in the west; both are then called cy- 
press or cedar. 
8. Thuja Arbor-vitae 
(A Greek name of some resinous evergreen) 
Small evergreen trees with flat twigs. Lvs. scale-like, oppos- 
ite, in 4 ranks ; two of the ranks have flat lvs., the other two 
have the lvs, folded or “keeled.” 
Pist. fl. about 2mm. across, greenish white; stam. fl. brown, 
3mm. across, each scale with 4 sporangia. Cone scales opposite, 
4-ranked, 8 or 10 in number. 
1. Twigs horizontal, with distinct upper and lower sides; cone dry, 
scales thin i. T. occidentals 
1. Twigs vertical, both sides alike; cone fleshy-knobbed 2 . T. orientals 
1. T. occidEntalis Western T. American Arbor-vitae 
Twigs mostly horizontal, always with upper and lower surfaces 
different. Cone scales thin, flat. 
Cult, common. 
Campus; Woods farm. 
