Arida arizonica – Arid Tansyaster
Scientific Name: Arida arizonica
Synonyms: Machaeranthera ammophila, M. arida, M. arizonica, M. coulteri var. arida, Psilactis coulteri
Common Names: Arid Tansyaster, Arid Machaeranthera, Desert Tansy-aster, Silver Lake Daisy
Growth Habit: Herb/Forb
Arizona Native Status: Native
Habitat: Desert, Riparian. This wildflower grows in dry, sandy areas, in alkali flats, in desert washes, along roadsides, and at the edges of desert streams and rivers.
Flower Color: Lavender, White
Flowering Season: Spring, Summer, Fall
Height: Up to 16 inches (40 cm) tall
Description: The small flower heads have more than 20 lavender or white rays, yellow disks, and mostly green, glandular, appressed to reflexed at the tip phyllaries in 2 to 3 series. The flower heads are followed by rounded, white, bristly seed heads. The leaves are green, alternate, glandular-hairy, oblanceolate to oblong in shape, and either pinnatifid or coarsely spine-toothed. The upper leaves are smaller and usually pressed up against the stem. The stems are green, slender, erect to ascending, branched, sticky, and covered with a mixture of glandular and non-glandular hairs.
The similar Dieteria bigelovii (Machaeranthera bigelovii) has flowers with spreading to reflexed phyllaries in 5 to 10 series. Dieteria asteroides (Machaeranthera asteroides) and Dieteria canescens (Machaeranthera canescens) have non-glandular phyllaries. Almutaster pauciflorus (Aster pauciflorus), Arida riparia (Machaeranthera riparia), Psilactis asteroides, and Psilactis gentryi have untoothed leaves. Machaeranthera tagetina has flowers with only up to 16 rays. Arida parviflora (Machaeranthera parviflora) has once or twice pinnatifid leaves and hairless or only sparsely gland-dotted stems. Machaeranthera tanacetifolia has fernlike or tansy-like, once or twice pinnatifid leaves.
Kingdom: Plantae – Plants
Subkingdom: Tracheobionta – Vascular plants
Superdivision: Spermatophyta – Seed plants
Division: Magnoliophyta – Flowering plants
Class: Magnoliopsida – Dicotyledons
Family: Asteraceae – Aster family
Genus: Arida (R.L. Hartm.) D.R. Morgan & R.L. Hartm.
Species: Arida arizonica (R.C. Jacks. & R.R. Johnson) D.R. Morgan & R.L. Hartm. – arid tansyaster