Prickly Plants

Flowers On Plants With Prickles

There are several families whose members contain plant parts that are prickly. Asteraceae (the sunflower family) has the thistles, Papaveraceae (the poppy family) has the Prickly Poppy, and of course, Cactaceae (cactus family) is known for its spines.

The common name, genus and species, and family are given for each flower.

Asteraceae

Sunflower Family

Thistles

All the thistles have toothed or wavy-margined leaves. Each tooth ends with a sharp spine. The phyllaries surrounding the flower also have spines.
Canada Thistle was introduced from Europe and is a noxious weed. It can take over whole fields.
Musk Thistle is also an alien species and is abundant in overgrazed fields.
Hooker Thistle is a native thistle. It has a very dense, large nodding head with many yellow flowerheads. The involucre bracts have spines on the margins. It has a basal rosette of spiny leaves. It is found on rocky slopes of the alpine and subalpine zones.

Canada Thistle

Breea arvensislkk or Circium arvense

Asteraceae

Musk Thistle

Carduus nutans

Asteraceae

Hooker, Alpine or Rocky Mountain Thistle

(at a distance)

Cirsium scopulorum

Asteraceae

Hooker, Alpine or Rocky Mountain Thistle

(close up)

Cirsium scopulorum

Asteraceae

Papaveraceae

Poppy Family

Prickly Poppy has 4 to 6 showy petals and numerous stamens. It has yellowish milky sap. Prickly Poppy is frequently seen along roadsides. It is common on the plains and outer foothills.

Prickly Poppy

(at a distance)

Argemone polyanthemos

Papaveraceae

Prickly Poppy

(close up)

Argemone polyanthemos

Papaveraceae

Cactaceae

Cactus Family

The plants in the Cactus Family are succulents (store water in thick stems). The spines are arranged in areoles (small groups). There are many petals, sepals and stamens.
Prickly Pear grows in sunny, rocky areas of the foothills.

Prickly Pear or Hunger Cactus

Opuntia polyacantha

Cactaceae