Flower:

Yellow sunflower 2 to 3½ inches across with 10 to 25 rays (petals). The center disk is usually purplish brown, sometimes yellow. When the weather is especially dry the petals fold up lengthwise or become twisted.

The bracts are short, wide and flattened, usually with a dull point at the tip and short hairs around the edges. One plant has 1 to several flowers at the end of long, mostly naked, branching stems.

Leaves and stem:

Leaves are 2 to 10 inches long and ¾ to 2¼ inches wide, typically shaped like the tip of a spear, with a very rough texture and short-stalked to stalkless. A pair of prominent lower veins run parallel to the center vein. The leaf edges have shallow, widely spaced teeth and short hairs. Color is dull gray-green, almost olive. Attachment is opposite and most leaves are in the lower part of the plant, but there may be small oval or lance-linear leaves widely spaced above the midpoint, which may be alternately attached. The stem is bristly and turns reddish brown with age.

Fruit:

The center disk forms a head of dry seed, each nearly ¼ inch long and without a tuft of hairs but with 2 bristly scales at the tip.

Notes:

Stiff Sunflower, formerly known by synonym Helianthus rigidus, is distinguished from other Minnesota native sunflowers by its mostly opposite, nearly stalkless, gray-green leaves, most of which are below the midpoint of the plant, plus flowers with a (usually) purplish brown center disk and flattened bracts with a dull point at the tip. It is one of the first sunflowers to bloom in summer. There are 2 recognized subspecies, both of which have widely overlapping ranges and both of which are found in Minnesota: subsp. pauciflorus, 2½ to 6 feet tall, which has leaves up to 10 inches long and usually has alternate stem leaves above the midpoint that have a long taper to a pointed tip, and subsp. subrhomboideus, 2 to 4 feet tall, which leaves only up to 5 inches long and has opposite leaves above the midpoint.