''Helianthus bolanderi'' is a species of

sunflower The common sunflower (''Helianthus annuus'') is a large annual forb of the genus ''Helianthus'' grown as a crop for its edible oily seeds. Apart from cooking oil production, it is also used as livestock forage (as a meal or a silage plant), as ...

known by the common names Bolander's sunflower and serpentine sunflower. It is native to

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 ...

and

Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...

, where it grows mainly in mountainous areas, often in

serpentine soil Serpentine soil is an uncommon soil type produced by weathered ultramafic rock such as peridotite and its metamorphic derivatives such as serpentinite. More precisely, serpentine soil contains minerals of the serpentine subgroup, especially anti ...

s. It has been found from southwestern Oregon as well as in northern and central California as far south as Santa Cruz County, with reports of a few isolated populations in southern California (some of them from urban areas and very likely cultivated or escaped specimens). This wild sunflower is an erect annual reaching heights over a meter (40 inches). It has a hairy, rough stem with leaves lance- or oval-shaped, usually pointed, sometimes serrated along the edges, and 3 to 15 centimeters (1.2-6.0 inches) long. 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 ...

holds one or more

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 ...

, and each plant may have many inflorescences growing along the full length of the stem. The flower head has a cup of long, pointed

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 ...

holding an array of bright yellow ray florets each one to two centimeters (0.4-0.8 inches) long around a center of yellow to dark purple or reddish

disc floret 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 ...

s. The

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 ...

is 3 to 5 millimeters (0.12-0.20 inches) long.Flora of North America, ''Helianthus bolanderi'' A. Gray, 1865. Bolander’s sunflower
/ref>

References

External links

* C.Michael Hogan, ed. 2010.
bolanderi''. Encyclopedia of Life

Jepson Manual TreatmentCalphotos Photo gallery, University of California
Flora of California Flora of Oregon bolanderi Plants described in 1865 {{Heliantheae-stub