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Idaho Mountain Wildflowers

Aster (Sunflower) Family: Asteraceae

Yellow daisy-like flowers (continued)

Hymenoxys, Old-man-of-mountain, Hymenoxys grandiflora (Torr. & A. Gray) K. F. Parker (left and right). The hymenoxys (sometimes classified as Tetraneuria grandiflora) is a true survivor. Its stems and leaves are covered with dense hair, reflected in the common name, "old-man-of-the mountain." This enables it to conserve metabolic heat, for  temperatures may go below freezing in early summer when it flowers. By remaining "prostrate" they are protected from wind and take advantage of the retained heat of the day. (The other plants in the image on the left, growing at ground level ,are spreading phlox, Phlox diffusa, and Artemisia tridentata, the common sage.)

Stemless hymenoxys, Hymenoxys acaulis (Pursh) Greene (left). The stemless hymenoxys is less well known than its alpine relative, although the flowerheads, one to a stem, with large central disks, suggest a kinship. Its rays are wide and their number varies; occasionally the plants are rayless. A mountain plant, it prefers rocky ground, growing as high as treeline. It too is sometimes classified as a Tetraneuria.

The Alpine Hulsea, Hulsea algida A. Gray, like the hymenoxys above—has adapted to living at and above treeline. It grows in protected warm crevices on talus slope, usually flowering late in the summer. Hulseas have thick, sticky, serrated leaves that give off an aromatic odor. Yellow flowerheads are borne on thick stems. The plants are named for US Army physician, Dr. G.W. Hulse; algida means “cold” in Latin, reflecting the plants' alpine environment. 

Common sunflower, Helianthus annuus L. (left). The common sunflower, originally native to North America, has spread throughout the world. The plant is immediately recognized by its large flowerhead, broad hairy leaves and tall stems. Helianthus, is from the Greek words for “sun” and “flower”; annuus, is Latin for “annual” (botanical names often mix Greek and Latin). Sunflowers bloom from mid-summer on, and are common in Idaho, growing at least as high as the montane zone in open fields, along fencelines and roadsides. Sunflowers have long been cultivated for their seeds, and more recently for the oil that the seeds contain.

Nuttall’s sunflower, Helianthus nuttallii Torr. & A. Gray (right). The genus Helianthus is a large one, made up of sixty-seven species; several grow in Idaho. Nuttall’s sunflower is a fairly common, tall, perennial plant characterized by sunflower-like flowerheads and narrow, lanceolate, mostly opposed leaves. The plants prefer moist or recently moist soil, and grow to fairly high elevations in our mountains.

Rocky Mountain dwarf sunflower, Helianthella uniflora (Nutt.) Torr. & A. Gray (left). Typically the dwarf sunflower has several long stems that arise from a thickened, persistent base (“caudex”). Large, opposing, lanceolate leaves are given off at intervals along the stems, each topped by a single (uniflora) sunflower-like flowerhead. The presence of the opposing leaves and the appearance of the flowerhead may suggest that the plant is an arnica. This plant, however has an involucre made up of many bracts (the little leaves below the flowerhead as shown in the inset) that vary greatly in size. Look for it in Idaho's foothills and lower mountain ranges in early to mid-summer.

Black-hairy prairie dandelion, Nothocalaïs nigrescens (L. H. Hend.) A. Heller (right). The prairie dandelion, the mountain dandelions,  hawkweeds, and several other yellow-rayed plants have common characterics: milky juice, taproots, dandelion-like pappuses, and lack diskflowers. Despite this plant’s name, “prairie-dandelion,” it is a mountain plant that grows only near the common borders of Wyoming, Montana and Idaho. The Latin species name, nigrescens, means “turning black,” for dark markings on the involucral bracts, the pointed leaves that cup the flower parts.

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