Aralia Spinosa - Description

Description

Aralia spinosa is an aromatic spiny deciduous shrub or small tree growing 2–8 m (6–25 ft) tall, with a simple or occasionally branched stem with very large bipinnate leaves 70–120 cm (28–48 in) long. The trunks are up to 15–20 cm (6–8 in) in diameter, with the plants umbrella-like in habit with open crowns. The young stems are stout and thickly covered with sharp spines. The plants generally grow in clusters of branchless trunks, although stout wide-spreading branches are occasionally produced.

The flowers are creamy-white, individually small (about 5 mm or 0.2 in across) but produced in large composite panicles 30–60 cm (12–24 in) long; flowering is in the late summer. The fruit is a purplish-black berry 6–8 mm (0.24–0.3 in) in diameter, ripening in the fall. The roots are thick and fleshy.

The doubly or triply compound leaves are the largest of any temperate tree in the continental United States, often about a meter (three feet) long and 60 cm (two feet) wide, with leaflets about 5–8 cm (2–3 in) long. The petioles are prickly, with swollen bases. In the autumn the leaves turn to a peculiar bronze red touched with yellow which makes the tree conspicuous and attractive.

The habit of growth and general appearance of Aralia spinosa and related tree-forming Aralia species are unique. It is usually found as a group of unbranched stems, rising to the height of 3.5–6 m (12–20 ft), which bear upon their summits a crowded cluster of doubly or triply compound leaves, thus giving to each stem a certain tropical palm-like appearance. In the south it is said to reach the height of 15 m (50 ft), still retaining its palm-like aspect. However, further north, the slender, swaying, palm-like appearance is most characteristic of younger plants that have not been damaged by winter storms.

• Bark: Light brown, divided into rounded broken ridges. Branchlets one-half to two-thirds of an inch in diameter, armed with stout, straight or curved, scattered prickles and nearly encircled by narrow leaf scars. At first light yellow brown, shining and dotted, later light brown.
• Wood: Brown with yellow streaks; light, soft, brittle, close-grained.
• Winter buds: Terminal bud chestnut brown, one-half to three-fourths of an inch long, conical, blunt; axillary buds flattened, triangular, one-fourth of an inch in length.
• Leaves: Clustered at the end of the branches, compound, bi- and tri-pinnate, three to four feet long, two and a half feet broad. The pinnae are unequally pinnate, having five or six pairs of leaflets and a long stalked terminal leaflet; these leaflets are often themselves pinnate. The last leaflets are ovate, two to three inches long, wedge-shaped or rounded at base, serrate or dentate, acute; midrib and primary veins prominent. They come out of the bud a bronze green, shining, somewhat hairy; when full grown are dark green above, pale beneath; midribs frequently furnished with prickles. Petioles stout, light brown, eighteen to twenty inches in length, clasping, armed with prickles. Stipules acute, one-half inch long.
• Flowers: July, August. Perfect or polygamomonoecious, cream white, borne in many-flowered umbels arranged in compound panicles, forming a terminal racemose cluster, three to four feet in length which rises, solitary or two or three together, above the spreading leaves. Bracts and bractlets lanceolate, acute, persistent.
• Calyx: Calyx tube coherent with the ovary, minutely five-toothed.
• Corolla: Petals five, white, inserted on margin of the disk, acute, slightly inflexed at the apex, imbricate in bud.
• Stamens: Five, inserted on margin of the disk, alternate with the petals; filaments thread-like; anthers oblong, attached on the back, introrse, two-celled; cells opening longitudinally.
• Pistil: Ovary inferior, five-celled; styles five, connivent; stigmas capitate.
• Fruit: Berry-like drupe, globular, black, one-fourth of an inch long, five-angled, crowned with the blackened styles. Flesh thin, dark.