EVERGREENS OF IOWA 
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Order 5. Ginkgoai.ES Ginkgo order 
Trees with cream-colored bark, and conical outline. Lvs. de- 
ciduous with broadly wedge-shaped base, a deep notch at apex, 
and fine forked veining, borne in groups on black, knoblike short- 
shoots. 
Stam. fl. l-2cm. long, catkin-like, a group of stalks, each bear- 
ing 2 large pollen sacs. Pist. fl. on another tree, a slender stalk 
2-3cm. long bearing 2 naked ovules at tip. Fruit a plumlike, 
fleshy seed, 2cm. in diameter, dull yellow ; inner seed coat shell- 
like enclosing endospern and a dicotyledonous embryo. 
Note: In 1897 it was annqunced that in these plants the egg-cell is fer- 
tilized in the seed about Sept. 1 by an active swimming sperm cell, as in 
ferns. This fact, with the veining of the leaf and many other details of 
structure and development, makes this tree precisely intermediate between 
the ferns and the pines. Probably no plant is of greater theoretical in- 
terest and importance. 
Family 4. Ginkgo ACE aE Ginkgo family 
Characters of the order 
Ginkgo Maiden-hair tree 
(The Chinese name) 
Characters of the order 
1. G. biloba Two-lobed G. 
The only species. 
Cult., rare. 
Campus ; 5th Ave. and Prince St. 
Native of China. 
Fl. May. Fr. Oct. 
Note: This is the last surviving species of a family of world-wide dis- 
tribution a few million years ago. Its ancestry runs back very clearly to 
the coal period, being related to the Cordaitales whose long parallel-veined 
lvs. cover almost every slab of Iowa coal. Ginkgo may occur wild in cen- 
tral China. It has been cultivated for ages about temples in China and 
Japan. The seeds are used for food. As it does not bloom until 25-30 yrs. 
old, no fls. have yet been seen* in Grinnell. This species is very desirable 
as a street and lawn tree. 
Order 6. ConiEEralEs Conifer order 
Trees or shrubs with needle-like or scalelike lvs.,. opposite or 
alternate or clustered, mostly evergreen. Wood, bark or lvs. 
resinous. 
Fls. monoecious or dioecious. Seeds borne on scales of a “cone” 
which may be fleshy and berry-like (naked in Taxus). 
Family 5. Pinaceae Pine Family 
Both pollen and ovules borne in catkin- or conelike groups, the 
ovules hidden at the base of young cone scales. 
