=Distribution.=--One of the most widely distributed of North American trees. It ranges from Labrador south to Pennsylvania, thence southwest to northern Mexico, and then north to northern Alaska. It is found at sea level and at elevations of 10,000 feet. There are records of its occurrence in all parts of Indiana. In all of its Indiana stations it grows only in low ground about lakes, swamps, ponds, low places between sand dunes, and along streams. In many places in the lake region it is found in almost pure stands over small areas. =Remarks.=--In Indiana this species is not of sufficient size and abundance to be of much economic importance. =JUGLANDÀCEAE.= The Walnut Family. Trees with large, aromatic, odd pinnate leaves; flowers appearing after the leaves unfold, the staminate in catkins, the pistillate solitary or in clusters; fruit a nut in a fleshy or hard fibrous shell; kernel edible or astringent. Pith of twigs chambered; staminate catkins thick, sessile or short stalked; stamens 8-40, glabrous; nuts with a network of rough projections 1 Juglans. Pith of twigs not chambered; staminate catkins slender, long-stalked; stamens 3-10, hairy; nuts more or less angled but smooth 2 Carya. =1. JÙGLANS.= The Walnuts. Trees with furrowed bark; pulp surrounding nut continuous, without lines of dehiscence on the surface. [Illustration: Plate 19. POPULUS TREMULOIDES Michaux. Quaking Aspen. (× 1/2.)] Bark gray, ridges smooth; upper part of leaf-scar of last year's twigs with a mat of hairs; pith dark-brown; fruit oblong, husk clammy 1 J. cinerea. Bark dark brown, ridges rough; upper part of leaf-scar of last year's twigs without a mat of hairs; pith light brown; fruit orbicular to slightly elongate, husk not clammy 2 J. nigra. =1.= =Juglans cinèrea= Linnæus. Butternut. Plate 20. A medium sized tree, usually less than 6 dm. in diameter; leaf-scars with upper margin convex or rarely notched; leaves 3-6 dm. in length; leaflets 7-19, the middle pairs the longest, clammy, almost sessile, oblong-lanceolate, 6-12 cm. long, fine serrate, rounded at base and acuminate at apex; flowers in May or June; fruit ripens in October, 4-8 cm. long with 4 prominent longitudinal ridges; kernel sweet and very oily; wood light, soft, not strong, coarse-grained but takes a good polish. =Distribution.=--Valley of the St. Lawrence River south to the Gulf States and west to Nebraska. Found in all parts of Indiana, although very sparingly in some counties. It is an infrequent tree in our range, and in only a few localities is it frequent or common. It is found along streams and in ravines, and in two instances it has been noted in old tamarack marshes. It prefers a well drained gravelly soil, and is rarely if ever found in a compact soil.