''Ionactis alpina'' (formerly ''Aster scopulorum''; common name lava ankle-aster) is a species of flowering plant in the family

Asteraceae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...

known by the common name lava aster. It is native to western United States from

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

Montana Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columbi ...

, where it grows in dry areas.University of Waterloo (Canada), Astereae Lab, ''Ionactis alpina'' Lava Ankle-aster
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Description

''Ionactis alpina'' is a perennial herb growing from a

caudex A caudex (plural: caudices) of a plant is a stem, but the term is also used to mean a rootstock and particularly a basal stem structure from which new growth arises.pages 456 and 695 In the strict sense of the term, meaning a stem, "caudex" is m ...

and fibrous root system. It produces a short, mostly erect, hairy stem up to in height. Most of the small leaves are on the lower part of the stem. They are up to about long, oval to lance-shaped and pointed, somewhat stiff and coated in hairs. The

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

bears solitary

flower heads A pseudanthium (Greek for "false flower"; ) is an inflorescence that resembles a flower. The word is sometimes used for other structures that are neither a true flower nor a true inflorescence. Examples of pseudanthia include flower heads, compos ...

with purple-green

phyllaries In botanical terminology, a phyllary, also known an involucral bract or tegule, is a single bract of the involucre of a composite flower. The involucre is the grouping of bracts together. Phyllaries are reduced leaf-like structures that form one or ...

, 7–21 thin blue, purple, or occasionally white ray florets surrounding 19–50 long yellow disc florets. The fruit is a hairy

achene An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and indehiscent (they do not ope ...

.Flora of North America, ''Ionactis alpina'' (Nuttall) Greene, 1897. Lava ankle-aster
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References

External links

Jepson Manual Treatment - ''Ionactis alpina''United States Department of Agriculture Plants Profile; Ionactis alpina
* Astereae Flora of the Western United States Plants described in 1834 Flora without expected TNC conservation status {{Astereae-stub