=Remarks.=--So far as the wood is concerned, the pecan is the poorest of all hickories. It has only about one-half the strength and stiffness of the shellbark hickory. Although the wood is inferior, the pecan has the distinction of producing the best nut of any native tree of America. The pecan was well known to the Indians, and some authors say the range of the species was extended by planting by the Indians. It has been a nut of commerce ever since the area of its range has been settled. It was planted by the pioneers, and recently nurserymen took up the subject of growing stock by budding and grafting from superior trees. At present there are about 100 horticultural varieties. The horticulturist has developed forms twice the size of the native nuts, and with shells so thin as to be styled "paper-shelled." The pecan has been extensively planted for commercial purposes in the southern states, but information obtained from owners of pecan trees in Indiana indicate that the winters are too severe for profitable pecan culture in Indiana. During the winter of 1917-18 the whole of a tract of 13 year old pecan trees on the Forest Reserve in Clark County was killed back to the ground. In Noble County about one mile south of Wolf Lake is a tree planted about 50 years ago that is about 9 dm. in circumference that frequently sets nuts but they never mature on account of the early frosts. =2.= =Carya cordifórmis= (Wangenheim) K. Koch. Pignut Hickory. Plate 23. Large tall trees with tight bark, usually a light gray, sometimes darker, fissures shallow and very irregular; twigs at first green, somewhat hairy, soon becoming smooth or nearly so, and a yellowish-brown, or reddish-brown by the end of the season; leaves and leaflets variable, the prevailing type of trees have smaller leaves with long and narrow leaflets, the unusual form has larger leaves up to 4 dm. in length with terminal leaflets up to 2 dm. in length and 8.5 cm. in width, and the last pair almost as large; fruit subglobose or rarely oblong, 2-3.5 cm. long; wings of sutures extending to below the middle, rarely one reaching the base; husk about 1.5 mm. thick, tardily separating to about the middle; nut ovoid or oblong, slightly flattened laterally, often as wide or wider than long, depressed, obcordate, with a short or long point at the apex, ovoid or rounded at the base, smooth or rarely with four distinct ridges; shell very thin and brittle; kernel very bitter; wood heavy, very hard, strong, tough and close-grained. It has about 92 per cent of the strength and about 73 per cent of the stiffness of shellbark hickory. [Illustration: Plate 23. CARYA CORDIFORMIS (Wangenheim) K. Koch. Pignut Hickory. (× 1/2.) The nuts are from different trees to show variation.]