The weed flora of Iowa Volume 4

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1913 Excerpt: ... there is a pair of leaves at each node and the two leaves are on opposite sides of the stem. Here the leaves are said to be opposite. Fia. 446. The clinging stem of the Bindweed, showing the alternate leaves. (After Thomfi.) In the asters, ironweed, goldenrods, lamb's quarter, etc., there is only one leaf at each node, and they are spoken of as alternate. In some cases several leaves appear at each node in a whorl. Such examples of whorled or verticillate leaves are found in the bedstraws and Joe Pye weed. BRANCHING. The outline of a blade is extremely various. When the general outline is completely filled out and the margin represents an even line, the leaf is said to be entire. Examples of such leaves are found in water pepper (Polygonum hydropiper), mild water pepper (P. hydropiperoides), Pennsylvania smartweed (P. pennsylvanicum), etc. Fia. 447. Leaf of the Privet plant showing entire margin. To designate the amount and character of the branching, the following terms are used: Via. 4 4 8. I. Triangular, lobed leaf of the Notch-weed. II. The rtnlfonn or kidney-shaped leaf of Ground Ivy, Illustrating wavy margin. III. Arrowshaped leaf of Bindweed. IV. Spear-shaped leaf of Sorrel. (After Thome.) Wavy margin, when the margin forms a wavy line bending slightly inward and outward in succession, as in the bitter dock (Rumex obtusifolius). Fio. 449. I. Leaf of Daisy, spatulate in shape with a serrate margin. II. Spiny-pointed, serrulate leaflet of alfalfa. III. Wavy-margined leaf of Pigweed (Amaranthus). TV. 'Ovate, dentate leaf of Snowball. V. Serrate leaf of Hen-bit (After ThomS.) Toothed or dentate, when the margin is cut into sharp teeth and the teeth point out, as in the lower leaves of the daisy fleabane (Erigeron annuus). Fio. 4 50. Cleft and pinnatlfld...