Cassia armata S. Watson
Senna armata (S. Watson) Irwin & Barneby Spiny senna, desert senna
Spiny senna is native to the North American southwest, a shrub with a dense tangle of sharp-tipped branches. They are leafless for most of the year, so when they aren’t flowering they look like someone gathered a heap of kindling and forgot about it. When they are flowering, it looks like someone lit it. They are found at elevations of 328-4593′ (100-1400 m), in sandy or gravelly washes. Plants: Shrubs up to 3′ (1 m) in height. They are densely branched, and many of the branches terminate in sharp spines. Tiny tubular hairs reflect the sun’s heat. Leaves: Leaves are on narrow branchlets, in 2-4 opposite pairs. Each leaflet is ⅛-3/16″ (4-6 mm) around, and ovate. Leaf pairs aren’t quite symmetric. Leaves are dropped entirely most of the time, in order to conserve water. Flowers: Yellow, or salmon pink, occurring singly or in clusters in leaf axils. Each flower has five petals, and is ⅝-⅞″ (1.6-2.4 cm) in diameter. Flower petals are not evenly distributed, so the flower has bilateral symmetry but not radial symmetry. Flowers appear from March to July. Fruits: Pods are ⅞-1½″ (2.5-4 cm) long, straight, and contain a few seeds. |
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Here are some similar species:
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You are here Senna armata |
Encelia farinosa |
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Common Name | |||||||||||||||||||||||||||||
Plant | Shrubs up to 3′ (1 m) in height. They are densely branched, any many of the branches terminate in sharp spines. | Forms rounded bushes 12-59″ (30-150 cm) high. | |||||||||||||||||||||||||||
Flowers | Yellow, or salmon pink, occurring singly or in clusters in leaf axils. Each flower has five petals, and is ⅝-⅞″ (1.6-2.4 cm) in diameter. Flower petals are not evenly distributed, so the flower has bilateral symmetry but not radial symmetry. Flowers appear from March to July. | Yellow flower stalks extend outward from the domelike bush. Each flower is 1-1¼″ (3-3.5 cm) around. Each is a composite flower, comprised of a central disc with many yellow or purple-brown disc florets, and yellow or orange-yellow ray florets. | |||||||||||||||||||||||||||
Leaves | Leaves are on long and narrow branchlets, in 2-4 opposite pairs. Each leaflet is ⅛-3/16″ (4-6 mm) around, and ovate. Leaf pairs aren’t quite symmetric. Leaves are dropped entirely most of the time. | Leaves are triangular (ovate to deltoid), blue-gray, and 1-3″ (3-8 cm) long. Fine matted plant hairs on the leaves give them a silvery appearance. | |||||||||||||||||||||||||||
Fruit | Pods are ⅞-1½″ (2.5-4 cm) long, straight, and contain a few seeds. | 1/16-3/16″ (3-6 mm). | |||||||||||||||||||||||||||
Range/ Zones | |||||||||||||||||||||||||||||
Habitats | In sandy or gravelly washes, at elevations of 328-4593′ (100-1400 m). | Dry, gravelly slopes and open sandy washes, at elevations up to 3281′ (1 km). | |||||||||||||||||||||||||||
Type | Wild | Wild |
Online References:
The Anza-Borrego Desert Natural History Association
CalPhotos (Photos)
Cassia armata S. Watson
Senna armata description by Thomas H. Kent, last updated 25 May 2020.
Range: