For the beginner, this can be a difficult group to identify because many of the vegetative traits which can be seen easily are shared by other families. The most definitive characteristics reside within the flowers, but due to the usual small size of the flowers and the variability they exhibit, it takes some experience to distinguish these characteristics with certainty.
Vegetative characteristics: Members of the family often are prickly, some are climbing, others are bushes or small trees. The leaves are generally alternate, (rarely opposite), and can be entire or variously lobed or palmately1 or pinnately compound and are usually without stipules.2
Floral Characteristics: The flowers are small greenish or white, radially symmetrical3 and can be one of the following: unisexual4 (the species then dioecious or polygamous) or bisexual.
The flowers are commonly in umbels5; but sometimes are racemose. The calyx usually has 5, more rarely 4 sepals, that are greatly reduced, sometimes to merely teeth, or there may be none. There are usually 5, but rarely 4 or 10, petals that are usually free, but can rarely be united to varying degrees, sometimes only at the tips. When sufficiently united, they fall as a unit . There are usually 5 stamens, more rarely there are 3 to many stamens. They are located in a ring inside the petals and generally alternate with the petals and like the petals, are attached to the top of the ovary, i.e. the ovary is inferior. The pistil is usually compound and made up of 5, but more rarely 1 to many carpels.6 There are usually more than 2 styles7 (sometimes many) that are usually free, but sometimes are joined together with lobed stigmas. The ovary is inferior8 and contains 2 to 15 cells, each with a single ovule (immature seed). The fruit is a berry9 or drupe which only rarely splits into segments.
As mentioned above, there is a great deal of variability in the Araliaceae with many of the nonfloral characteristics being shared by various other families. The ovary being inferior to the other floral parts, the multi celled inferior ovary with just a few seeds, the petals and stamens often of the same number and the rudimentary or totally lacking calyx generally identify the Family. The small size of the flowers, however, will require some type of magnification and some experience in the dissection of these small parts.
The Araliaceae is economically not an especially valuable plant family as are the timber trees for example. There are a number of the family members that are used as house plants, English Ivy as an example. In warmer southern states many of these can be used as ornamental garden plants. The rice paper plant (Tetrapanax papyriferus) is the source of rice paper. The aromatic root of wild sarsaparilla (Aralia nudicaulis) is used as a substitute for sarsaparilla. Panax ginseng has for many years been used by the Chinese for the treatment of various ills. Panax quinquefolium is used in the U.S. as a stimulant.[3 & 15]
Devil’s walkingstick, Hercule’s club, Angelica tree
Scientific name: Aralia spinosa
Origin: Native to North America
Plant description: Aralia spinosa is a few branched, flat-topped bush or small tree that grows to a height of 12 m (~39ft) and sprouts from the root system forming clonal thickets. The trunk frequently develops few if any branches and the plant becomes an erect trunk with
a crown of leaves.[13] The plant stem, branches and often the petioles1
and leaf rachis2 are armed with stout prickles.
A short discussion concerning leaf structure is appropriate here. In the accompanying illustrations, each illustration represents an entire leaf. The smaller subparts of the compound leaves are referred to as leaflets. Simple leaves, such as in maple, are not divided into leaflike structures (leaflets), though they may be deeply cleft. Compound leaves generally come in two forms: Palmately compound leaves, such as those of horse chestnut, have their leaflets spread out like the fingers of a hand, whereas pinnately compound leaves have their leaflets attached to a central ‘stem’ (axis or rachis) much like the two sides of a feather. The stem below the attachment of the bottom leaflets or the stem of a simple leaf is referred to as a petiole. The leaflets of a pinnately compound leaf can be attached to the rachis in either an opposite or alternate configuration. At the base of both simple leaves and compound leaves an abscission layer is formed that allows the leaf to break away from the more permanent stem to which it is attached. For both compound and simple leaves there generally is also a bud at this location though it may not be obvious and will require some more investigation on your part to be seen. This bud will become the next leaf if there is to be a leaf there, as for example, next year. If there is a bud there, and the leaflets are without associated buds, you can be quite certain that the leaf is compound. If there is later a replacement leaf, it will be derived from the bud at the base of the leaf. Alternatively, if there are buds at what you suspect are leaflets of a compound leaf, you are not dealing with a compound leaf.
Pinnately compound leaves can have leaflets that are themselves compound and even those divisions can be compound and so on. The accompanying illustrations provide examples of unipinnate, bipinnate and tripinnate leaves.
The leaves of…
