G WEED FLORA OF IOWA 



EQUISETACEAE, HORSETAIL FAMILY. 



This small family of rushlike plants contains a few species only 

 and but one that is weedy. 



Common Horsetail (Equisetum arvense L.). 



Description.- — A rushlike perennial with running rootstocks and 

 annual stems; branches in whorls; fertile and sterile plants, the 

 fertile appearing early in spring with a terminal cone, yellowish 

 in color, bearing the spore cases (sporangia) underneath a scale; 

 spores provided with hygroscopic bands; sterile frond with 

 whorled branches. 



Distribution. — Widely distributed in North America, common in 

 sandy moist fields, on railroad embankments; common in Story, 

 Boone, Carroll, Crawford, Harrison, Woodbury, Clinton, Dubuque, 

 Lee, Page, Polk, Cerro Gordo, Emmet, Webster, Marshall, Johnson, 

 Winneshiek and Allamakee counties 



Extermination. — This is a most persistent perennial; only by giv- 

 ing frequent shallow cultivation after small grain is removed 

 during the summer can the weed be kept in check. 



SPERMATOPHYTA, FLOWERING PLANTS. 



The seed plants have stamens and pistils and reproduce by seeds. 

 Represented by the pine, spruce, hemlock, wheat, rye, corn, rose, 

 maple, ash, aster, goldenrod, squash, etc. 



GYMNOSPERMAE, GYMNOSPERMS. 



The seeds are not inclosed in an ovary. Trees or shrubs gener- 

 ally with needlelike or scalelike leaves; represented in Iowa by 

 the red cedar, white pine, etc. None are weedy. 



ANGIOSPERMAE, ANGIOSPERMS. 



Ovules borne in a closed ovary. Represented by a large number 

 of our native and cultivated plants, like wheat, corn, lily, rose, 

 clover, tomato, etc. 



MONOCOTYLEDONEAE, MONOCOTS. 



Plants with endogenous stem, the woody fibers in bundles dis- 

 tributed through the pith. Annual ring absent. Flowers gen- 

 erally on the plan of 3 ; embryo with a single cotyledon. Corn, 

 lily, onion, asparagus, blue grass, switch grass are representatives. 



