Eryngium racemosum is a rare species of flowering plant in the carrot family

Apiaceae

The Apiaceae , commonly known as carrot or parsley family, is a group of mostly aromatic plants with hollow stems. The family is large, with more than 3,700 species spread across 434 genera, it is the sixteenth largest family of flowering plants...

 known by the common name delta eryngo, or delta button celery.

Distribution

It is endemic to California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

, where it is known from the Sacramento-San Joaquin River Delta region of the Central Valley up to the rise of the Sierra Nevada foothills. It is a plant of vernally wet and flooded areas near the waterways of the valley, habitat which has been altered and in some areas eliminated by human activity. It is also a member of the flora in the rare alkali sink habitat of the delta. The plant has no federal listing but it is listed as an endangered species

Endangered species

An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...

 on the California state level.

There are 26 reported occurrences of the plant, but several of these no longer exist, having been extirpated

Local extinction

Local extinction, also known as extirpation, is the condition of a species which ceases to exist in the chosen geographic area of study, though it still exists elsewhere...

. Threats to the species include habitat destruction via alteration of water regimes and water diversion, changes to waterways by dredging and other maintenance activities, conversion of land to agriculture

Agriculture

Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...

, and non-native plant species

Introduced species

An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...

. The plant relies on the seasonal flooding that would occur naturally in the delta; this flooding is strictly contained and prevented today.

Description

Eryngium racemosum is is a mostly prostrate perennial herb with a slender, branching stem spreading to a maximum length near half a meter. The stem may root at nodes that come in contact with moist soil. The serrated or lobed leaves have blades a few centimeters long and are borne on longer petioles

Petiole (botany)

In botany, the petiole is the stalk attaching the leaf blade to the stem. The petiole usually has the same internal structure as the stem. Outgrowths appearing on each side of the petiole are called stipules. Leaves lacking a petiole are called sessile, or clasping when they partly surround the...

. The inflorescence

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. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...

 is a raceme of rounded or oval flower heads, each surrounded by five long, narrow, spiny bract

Bract

In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis, or cone scale. Bracts are often different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture...

s. The flowers in the head bloom in white or purple-tinged petals in June through September.