COMMON TREES (MAK)

FORM: By tree "form" is meant the general shape of the tree, as expressed by the growth of the branches off the trunk. Most trees tend to an oval or rounded shape, although the vase shape is very common. In vase-shaped, the main branches grow up and out. In a spreading form, the main lateral branches tend to spread widely outwards creating an umbrella shape. In a columnar form, the branches are all short relative to the trunk. The forms intergrade and the shape a tree takes can depend on a number of factors. Thus, this characteristic is liberally applied in the key. Palms have one growth tip per trunk and therefore lack branches.

BARK TYPE: Tree bark types are illustrated in a series of photographs at MAK Barks Illustrated, In the field, the type or form of the bark should be viewed on the lower part of the trunk and on the oldest specimen present. Younger trees may have more or less smooth or finely grooved bark that will mature over time into a more complex type.

LEAF - ARRANGEMENT: Leaf arrangement describes how the leaves are borne on the stem (either alternating or in pairs, opposite each other along the stem; sometimes both arrangements can be present) and whether leaves are simple or compound *. Compound leaves are divided into leaflets and these can range in number from 2 to many per leaf. Leaflets may or may not be opposite on the rachis. Compound odd means the number of leaflets is an odd number: leaflets are paired, with one additional at tip of leaf. Compound even has all leaflets paired. LEAF - SHAPE: The shape and characteristics of a leaf can be described in many ways. To simplify, this MAK key considers only the most basic of shapes: the leaf is either narrow (linear), "ovate" (most leaves), or broad (nearly as wide or wider than long); the tip of the leaf is either pointed (acute) or rounded (blunt). Basic shape can be applied to leaflets of compound leaves. A few additional leaf characteristcs are found under "OTHER". Illustrations of these various leaf types is provided at MAK Leaf Types Illustrated

INFLORESCENCE: Flowers are important structures to aid in identifying a particular tree to genus, but often the tree is encountered outside its flowering period. Vegetative (non-flower) characteristics should be sufficient to produce a short list of candidates in most cases. FLOWER: Flower colors cover an extremely wide range, so here the colors are grouped, limiting that to a color set (for example: red and orange, blue and purple).

FRUIT: The fruit borne on a tree can be an exceptionally good characteristic for identifying the plant. Unfortunately, the variety of fruit types and the unfamiliarity of most non-botanists with the rich terminology applied to fruit types makes this property one difficult to characterize in a simple way. The approach used here is to consider fruit types as either dry or fleshy (soft; example: edible friuits). Dry fruits are either membranous (a dry capsule), or some woody or hard form (for example, a nut). Bean-like fruits have seeds in a pod (legumes– Family Fabaceae) are singled out as these are found on a large number of common tree species.

OTHER: A tree may have a distinct property that can be used to set it apart from many other species: having spines or thorns, or a distinct odor (aromatic) detected by smelling a crushed leaf. Special leaf characteristics are also noted here: falcate = blade linear, curved; discolorous = the underside of leaf is distinctly different in color from the upper surface; peltate = the leaf stem (petiole) attaches to the blade inside the blade margin. Because these are very distinct characteristics, selecting one will eliminate species lacking the characteristic.

* Learning to differentiate between simple and compound leaf form can be critical to succeeding in differentiating species with this key.



	CPIE MultiAccess Key (MAK): Common Trees of Hawai‘i NOTE: FUNCTIONAL, BUT DATABASE PRESENTLY HAS TOO FEW SPECIES to MAK homepage. AECOS logos below on right and bottom will affect a return to AECOS website homepage.

	Plant is a tree with a woody stem and typically over 2-3 m (6-10 ft) in height. Besides being woody, the main stem of a tree is distinguishable as a "trunk". A "shrub" or "bush" differs in having multiple, extensively branched, main stems and generally smaller stature. Some trees are shrub-like when young, gradually sheding lower branches as the trunk develops. The number of different kinds of trees in Hawai‘i is not known; the DB "MAK_5" presently contains 51 taxa of eudicot trees. Eudicots are angiosperms (flowering plants) excluding groups such as palms and bamboos (these are monocot angiosperms). Bamboos are grasses and can be identified using the MAK Grass Key. Trees can be difficult to identify in the field for the reason that access to leaves, flowers, and fruit may be limited by the height of the trunk. In many cases, encountering an unknown tree presents only a good look at the bark and the general form of the tree as seen from a distance. Searching the ground around a tree can provide leaf shape and sometimes fallen flowers or fruit. This key is an attempt to overcome those limitations, providing a list of potential species names from whatever information can be provided. For this reason, emphasis is put on the type of bark and general leaf characteristics. Although typically not always described in tree descriptions, identifying trees by their bark is a valid and useful approach (DiLornardo, 2019) if limitations are taken into account (see BARK TYPE below). SPECIAL NOTE ON EUCALYPTS—Providing a key that is truely useful requires entering a large proportion of the species known to be in Hawai‘i into the database and coding these as accurately as possible. This key includes all the species of Eucalypytus, but many are not yet thoroughly coded. A separate key to the Family Myrtaceae (includes all the eucalypts) is now available. SPECIAL NOTE ON GYMNOSPERMS—The MAK_5 DB includes only flowering trees and no palms. A separate key to the Pinopsida gymnosperms (conifers) must be used if you suspect the tree you hope to identify is a conifer (pine, cypress, redwood).		DATABASE: MAK_5 TOTAL DB TAXA: 51 (51 LINES) LINES MATCHED: 0 REJECTED: 0
			SELECTED CHARACTER MATCH GENERAL DESCRIPTION (based on selections): Match codes you selected:
Select a best choice (or none) from each category:			Species - Common Name	Status Family		Reference List
		TREE FORM narrow, columnar oval/rounded vase-shaped spreading unbranched trunk with crown BARK TYPE smooth peeling finely grooved coarse vert. ridges scales plates soft, friable LEAF ARRANGEMENT simple, alternate simple, opposite compound, palmate compound (odd) pinnate compound (even) pinnate LEAF SHAPE narrow, linear ovate, tip acute ovate, tip rounded/blunt broad broad and lobed heart-shaped INFLORESCENCE axilary few-flowered paniculate spike-like umbellate FLOWER (SHAPE) regular, radial symmetry bilateral symmetry irregular (dense spike) FLOWER (COLOR) mostly white yellow red (pink) or orange purple to blue green FRUIT dry, membranous dry, solid or woody soft, leathery soft, fleshy bean-like, pod OTHER CHARACTERISTIC thorns or spines aromatic leaf discolorous leaf falcate leaf peltate	FORM: By tree "form" is meant the general shape of the tree, as expressed by the growth of the branches off the trunk. Most trees tend to an oval or rounded shape, although the vase shape is very common. In vase-shaped, the main branches grow up and out. In a spreading form, the main lateral branches tend to spread widely outwards creating an umbrella shape. In a columnar form, the branches are all short relative to the trunk. The forms intergrade and the shape a tree takes can depend on a number of factors. Thus, this characteristic is liberally applied in the key. Palms have one growth tip per trunk and therefore lack branches. BARK TYPE: Tree bark types are illustrated in a series of photographs at MAK Barks Illustrated, In the field, the type or form of the bark should be viewed on the lower part of the trunk and on the oldest specimen present. Younger trees may have more or less smooth or finely grooved bark that will mature over time into a more complex type. LEAF - ARRANGEMENT: Leaf arrangement describes how the leaves are borne on the stem (either alternating or in pairs, opposite each other along the stem; sometimes both arrangements can be present) and whether leaves are simple or compound . Compound leaves are divided into leaflets and these can range in number from 2 to many per leaf. Leaflets may or may not be opposite on the rachis. Compound odd* means the number of leaflets is an odd number: leaflets are paired, with one additional at tip of leaf. Compound even has all leaflets paired. LEAF - SHAPE: The shape and characteristics of a leaf can be described in many ways. To simplify, this MAK key considers only the most basic of shapes: the leaf is either narrow (linear), "ovate" (most leaves), or broad (nearly as wide or wider than long); the tip of the leaf is either pointed (acute) or rounded (blunt). Basic shape can be applied to leaflets of compound leaves. A few additional leaf characteristcs are found under "OTHER". Illustrations of these various leaf types is provided at MAK Leaf Types Illustrated INFLORESCENCE: Flowers are important structures to aid in identifying a particular tree to genus, but often the tree is encountered outside its flowering period. Vegetative (non-flower) characteristics should be sufficient to produce a short list of candidates in most cases. FLOWER: Flower colors cover an extremely wide range, so here the colors are grouped, limiting that to a color set (for example: red and orange, blue and purple). FRUIT: The fruit borne on a tree can be an exceptionally good characteristic for identifying the plant. Unfortunately, the variety of fruit types and the unfamiliarity of most non-botanists with the rich terminology applied to fruit types makes this property one difficult to characterize in a simple way. The approach used here is to consider fruit types as either dry or fleshy (soft; example: edible friuits). Dry fruits are either membranous (a dry capsule), or some woody or hard form (for example, a nut). Bean-like fruits have seeds in a pod (legumes– Family Fabaceae) are singled out as these are found on a large number of common tree species. OTHER: A tree may have a distinct property that can be used to set it apart from many other species: having spines or thorns, or a distinct odor (aromatic) detected by smelling a crushed leaf. Special leaf characteristics are also noted here: falcate = blade linear, curved; discolorous = the underside of leaf is distinctly different in color from the upper surface; peltate = the leaf stem (petiole) attaches to the blade inside the blade margin. Because these are very distinct characteristics, selecting one will eliminate species lacking the characteristic. * Learning to differentiate between simple and compound leaf form can be critical to succeeding in differentiating species with this key.		NOTES: The TERMINOLOGY used in this key may not always match exactly that used by botanists, being adapted here to make this key more accessible to the casual user. Read the paragraphs presented on this page in column to left to find definitions for terms used here to describe trees. CONFIRMING AN IDENTIFICATION will require careful consideration of the species description provided in the reference link or some other source (see References for other suggestions). "MAN" refers to Vols 1 & 2 of Manual of the Flowering Plants of Hawai‘i by Wagner, Herbst, and Sohmer; "S&H" refers to A Tropical Garden Flora by Staples and Herbst. A number in brackets indicates that a photo or drawing is provided in the referenced source (gives plate number in the Manual). These reference sources are known to provide a species description (and figure) on the page indicated. However, the casual user may find that a search of the internet for each of the taxa on the short list of possible identifications can provide a clinching photo or species decription, and is a logical next step whether one or several species are listed. STATUS CODES presented are as follows: "End" = an endemic species; "Ind" = an indigenous species; "Nat" = a naturalized species; "Pol" = an early Poynesian introduction ("canoe plant"); and "Orn" = an ornamental species, not naturalized. A question mark should be read as "probably".		Clear form to start of key

Common Trees of Hawai‘i