| A. Pores in the summer wood minute, scattered singly or in groups, or in
short broken lines, the course of which is never radial. | |
| 1. Pith rays minute, scarcely distinct. | |
| a. Wood heavy and hard; pores in the summer wood not in clusters. | |
| a'. Color of radial section not yellow. | Ash. |
| b'. Color of radial section light yellow; by which, together
with its hardness and weight, this species is easily recognized. | Osage Orange. |
| b. Wood light and soft; pores in the summer wood in clusters of 10 to 30. | Catalpa. |
| 2. Pith rays very fine, yet distinct; pores in summer wood usually single
or in short lines; color of heart-wood reddish brown; of sap-wood
yellowish white; peculiar odor on fresh section. | Sassafras. |
| 3. Pith rays fine, but distinct. | |
| a. Very heavy and hard; heart-wood yellowish brown. | Black Locust. |
| b. Heavy; medium hard to hard. | |
| a'. Pores in summer wood very minute, usually in small clusters of
3 to 8; heart-wood light orange brown. | Red Mulberry. |
| b'. Pores in summer wood small to minute, usually isolated; heart-wood
cherry red. | Coffee Tree. |
| 4. Pith rays fine but very conspicuous, even without magnifier. Color of
heart-wood red; of sap-wood pale lemon. | Honey Locust. |
| B. Pores of summer wood minute or small, in concentric wavy and sometimes
branching lines, appearing as finely-feathered hatchings on tangential
section. | |
| 1. Pith rays fine, but very distinct; color greenish white. Heart-wood
absent or imperfectly developed. | Hackberry. |
| 2. Pith rays indistinct; color of heart-wood reddish brown; sap-wood
grayish to reddish white. | Elms. |
| C. Pores of summer wood arranged in radial branching lines (when very
crowded radial arrangement somewhat obscured). | |
| 1. Pith rays very minute, hardly visible. | Chestnut. |
| 2. Pith rays very broad and conspicuous. | Oak. |
| D. Pores of summer wood mostly but little smaller than those of the spring
wood, isolated and scattered; very heavy and hard woods. The pores of
the spring wood sometimes form but an imperfect zone. (Some diffuse-porous
woods of groups A and B may seem to belong here.) | |
| 1. Fine concentric lines (not of pores) as distinct, or nearly so, as the
very fine pith rays; outer summer wood with a tinge of red; heart-wood
light reddish brown. | Hickory. |
| 2. Fine concentric lines, much finer than the pith rays; no reddish tinge
in summer wood; sap-wood white; heart-wood blackish. | Persimmon. |
Sassafras and mulberry may be confounded but for the greater weight and hardness and the absence of odor in the mulberry; the radial section of mulberry also shows the pith rays conspicuously.
Honey locust, coffee tree, and black locust are also very similar in appearance. The honey locust stands out by the conspicuousness of the pith rays, especially on radial sections, on account of their height, while the black locust is distinguished by the extremely great weight and hardness, together with its darker brown color.
Fig. 131. Wood of Coffee Tree.
The ashes, elms, hickories, and oaks may, on casual observation, appear to resemble one another on account of the pronounced zone of porous spring wood. (Figs. 129, 132, 135.) The sharply defined large pith rays of the oak exclude these at once; the wavy lines of pores in the summer wood, appearing as conspicuous finely-feathered hatchings on tangential section, distinguish the elms; while the ashes differ from the hickory by the very conspicuously defined zone of spring wood pores, which in hickory appear more or less interrupted. The reddish hue of the hickory and the more or less brown hue of the ash may also aid in ready recognition. The smooth, radial surface of split hickory will readily separate it from the rest.
