ACER SACCHARUM Marshall. Sugar Maple. (× 1/2.)
The sugar maple on account of its slow growth has not been used much in reforestation. It is very tolerant of shade, can adapt itself to almost all kinds of soils, thrives either in a pure or mixed stand, and is practically free from injury of insects and diseases. It has, however, been extensively used as a shade tree. For this purpose it is scarcely excelled by any other tree. When grown in the open it almost invariably assumes a symmetrical oval form, and the autumnal coloration of its foliage is rarely surpassed by any of our trees. Where a large tree is desired for street or ornamental planting the sugar maple can safely be recommended.
5a. Acer saccharum variety Rugélii (Pax) Rehder. This variety of the sugar maple has leaves much wider than long, smaller and 3-lobed. The lobes are long acuminate and usually entire, sometimes the lower lobe has a small lobe near the base. This variety is included in our flora on the authority of C. S. Sargent who has given this name to specimens from Indiana in the writer's herbarium. The specimens so named are from the southern part of the State. While there is a wide range of difference in the shape of the leaves of the typical 5-lobed Acer saccharum and its variety Rugelii, all intermediate forms can be easily found. The leaves of a tree will vary most on those trees whose average shaped leaves are farthest from the typical form.
5b. Acer saccharum variety Schnéckii Rehder. This variety in its extreme form is well marked by having the petioles and under surface of the leaves densely covered with hairs. The variety is characterized by having a "fulvous pubescence," but the 18 specimens at hand show the color of the pubescence on both young and mature specimens to range from white to fulvous. The leaves of all specimens at hand are 5-lobed and show a variation of leaves with petioles and under surface of leaves densely pubescent to those with petioles glabrous and with densely pubescent under surface. The habitat is that of a dry soil and associated with beech. It has been found in Gibson, Martin, Perry, Posey and Vanderburgh counties.