in the southeast part of the State. Throughout its range in Indiana where it is found in low ground, it is in places rich in organic matter, except in the "flats" of the southern part of the State where it grows in a hard clay soil with sweet gum, red birch, etc. In contrast the silver maple is generally found growing in wet places with little organic matter; especially is this true in the lower Wabash bottoms. The red maple grows also on high ground. In the northern part of the State it is only an occasional tree of gravelly ridges or on high ground about lakes or along streams. In the southern part of the State it is a local to a frequent tree in most parts of the "k.n.o.b" area where it is a.s.sociated with white oak, black oak, black gum, etc. It is also an occasional tree on the top of bluffs and cliffs.

=Remarks.=--The red maple is not abundant enough in Indiana to be of any economic importance. It grows rapidly and should replace the silver maple for shade tree planting since its branches are not broken off as easily by ice storms and it is more resistant to insect attack.

=3a. Acer rubrum= variety =Drummondii= (Hooker and Arnott) Torrey and Gray. This variety of the red maple is a form found in the dense swamps of the lower Wabash Valley. It is distinguished from the type by its twigs which generally remain more or less hairy until maturity; by the under surface of the leaves remaining more or less tomentose during the summer, and by its larger fruit. This variety is known with certainty only from Little Cypress Swamp in Knox County about 12 miles southwest of Decker. Here it is a frequent to a common tree a.s.sociated with cypress, swell-b.u.t.t ash, b.u.t.ton-bush, sweet gum, etc. All of the trees of this locality have 5-lobed leaves.

[Ill.u.s.tration: Plate 113.

ACER RUBRUM Linnaeus. Red Maple. ( 1/2.)]

A specimen collected in the "bottoms" about two miles east of Huntingburg in Dubois County has 3-lobed leaves which are tomentose beneath at fruiting time and has fruit intermediate in size between the type and variety _Drummondii_ which I doubtfully refer to variety tridens Wood.

=4. Acer ngrum= F. A. Michaux. Black Maple. Black Sugar. Plate 114.

Medium to large sized trees with dark furrowed bark on old trees; leaves a little wider than long, 6-15 cm. long, on petioles usually 3-15 cm.

long which are more or less swollen at the base and by maturity develop a scale like appendage on each side of the petiole at the base--especially on each of the terminal pair of leaves, sometimes with foliar stipules which are 2-3 cm. long on stalks of equal length, leaves with three main lobes, the two lower lobes generally have a small lobe at their base, margins of lobes entire and undulating, sinuses between main lobes generally rounded at the base, wide and shallow, base with a narrow sinus, the lower lobes often overlapping, rarely somewhat dentate, dark green above and a paler yellow green below, hairy on both surfaces when young, becoming at maturity glabrous above and remaining more or less p.u.b.escent beneath; flowers appear in May when the leaves are about half grown on long hairy pedicels, the staminate and pistillate in separate cl.u.s.ters on the same or different trees; fruit matures in autumn, the samaras about 3 cm. long.

=Distribution.=--Quebec to Georgia, west to South Dakota and south to Louisiana. Found in all parts of Indiana and invariably a.s.sociated with sugar maple, and often with beech in addition. Frequently almost pure stands of sugar maple may be found with the black maple absent. Where found it is usually a frequent to common tree, and when it occurs on a wooded slope it is more frequent near the base and appears to be able to advance farther into moist situations than its congener.

=Remarks.=--This tree cannot be distinguished from the sugar maple by its form, but at short range can be separated from it by its richer green foliage and by the drooping habit of the lower lobes of the leaves. It is commonly separated from the sugar maple by the darker color and by the narrower and shallower furrows of the bark, but these characters will not always separate the two species. Hence, when buying black maple trees from a nurseryman you may receive the sugar maple.

Those who distinguish the two species agree that the black maple is the more desirable tree for shade tree planting. The black and sugar maple are the two most desirable trees for shade tree planting in Indiana.

They are long lived, have a very desirable form, beautiful foliage, a long leaf period, and are quite free from disease and insect injury.

[Ill.u.s.tration: Plate 114.

ACER NIGRUM. F. A. Michaux. Black Maple. ( 1/2.)]

=5. Acer saccharum= Marshall. Sugar Maple. Sugar Tree. Hard Maple. Rock Maple. Plate 115. Usually large, tall trees. The bark of small trees is smooth or rough, becoming fissured on old trees, tight or on very old trees sometimes the ridges loosen on one edge and turn outward. The leaves are extremely variable on different trees, and frequently show a wide variation on the same tree, as to form and in the presence or absence of hairs on the petioles and on the under surface of the leaves.

In our area all of the forms which have the majority of the leaves longer than wide or about as wide as long, may be considered as falling within the type. The average sized leaves are 6-12 cm. long, 3-5 lobed, more or less cordate at the base, generally with a broad sinus, sometimes truncate or slightly wedge-shape, sinuses generally wide-angled and rounded at the base, sometimes acute, hairy beneath when young, becoming smooth at maturity except for a few hairs along the veins or in the main axils of the veins, or sometimes remaining more or less p.u.b.escent over the whole under surface, more or less glaucous beneath; flowers appear in April or May, on hairy pedicels 3-7 cm. long, the staminate and pistillate in cl.u.s.ters on the same or different trees; fruit ripening in autumn, samaras glabrous and usually 2-4 cm. long.

=Distribution.=--Newfoundland to Georgia, west to Manitoba and south to Texas. A frequent to a very common tree in all parts of Indiana. It is confined to rich uplands, or along streams in well drained alluvial soil. Throughout our area it is constantly a.s.sociated with the beech. It is absent in the "flats" of the southeastern part of the State, and on the crest of the ridges of the "k.n.o.b" area of Indiana, but it is a frequent or common tree on the lower slopes of the spurs of the "k.n.o.bs."

=Remarks.=--The under surface of the leaves of the sugar maple in the northern part of its range are green, while those of the southern part of its range are quite glaucous beneath. To distinguish these two intergrading forms the southern form has been called =Acer saccharum= var. =glauc.u.m= Sargent[61]. All of the trees seen in Indiana have leaves more or less glaucous beneath. This character, however, is not always evident in dried specimens. The writer prefers not to apply the varietal name to the forms of our area. The sugar maple always has been and will continue to be one of the most important trees of the State. In its ma.s.s distribution in Indiana it ranks not less than third. In the quality and uses of its wood it is equalled or exceeded only by the oak, ash and hickory. When compared with white oak it is a little lighter but thirty per cent stronger and fifty-three per cent stiffer. The greatest amount of the annual cut of maple is worked into flooring which is shipped to all parts of the world. It is much used in the manufacture of furniture and ranks third in use for veneer and hard wood distillation, and as a fuel wood is excelled only by hickory. Since pioneer times, the sap of this tree has been made into sirup and sugar and their manufacture now forms a valuable industry. On an average it takes 3 to 4 gallons of sap to make a pound of sugar, and an average sized tree will annually yield about 3 to 4 pounds of sugar.

[Ill.u.s.tration: Plate 115.

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 a.s.sumes a symmetrical oval form, and the autumnal coloration of its foliage is rarely surpa.s.sed 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 =Rugelii= (Pax) Rehder. This variety of the sugar maple has leaves much wider than long, smaller and 3-lobed. The lobes are long ac.u.minate 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 =Schneckii= 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 p.u.b.escence," but the 18 specimens at hand show the color of the p.u.b.escence 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 p.u.b.escent to those with petioles glabrous and with densely p.u.b.escent under surface. The habitat is that of a dry soil and a.s.sociated with beech. It has been found in Gibson, Martin, Perry, Posey and Vanderburgh counties.

=AESCULaCEAE.= The Buckeye Family.

=AeSCULUS.= The Buckeyes.

Trees with dark or ashy-gray colored bark; twigs stout; buds large, leaves opposite, palmately divided into 5-9 ovate or oblong divisions, the divisions serrate; flowers in terminal panicles; fruit a 3-lobed capsule. The fruit is poisonous to stock, although it rarely proves fatal.

Anthers protruding from the flower; fruit warty 1 A. glabra.

Anthers included in the flower; fruit smooth 2 A. octandra.

=1. aesculus glabra= Willdenow. Buckeye. Plate 116. Medium to large sized trees[62]; bark of old trees fissured, not tight; branchlets robust; twigs at first more or less p.u.b.escent, remaining more or less hairy until maturity; leaves large, 5-foliate, rarely 6 or 7 foliate, petioles more or less p.u.b.escent; leaflets sessile or on very short stalks, ovate-oblong, oval-oblong, or obovate, about 1 dm. long, ac.u.minate, narrowed to a wedge-shaped base, more or less p.u.b.escent beneath until maturity, especially along the princ.i.p.al veins, margins irregularly serrate except near the base; flowers generally appear in May when the leaves are almost full size, but in the southern part of the State the flowers sometimes appear the last of March, flower cl.u.s.ters 1-1.5 dm.

long, the whole inflorescence usually densely covered with white hairs, flowers pale-greenish yellow; fruit a globular spiny capsule, generally 3-6 cm. in diameter, which usually contains 1-3 large glossy chocolate-colored nuts.

The p.u.b.escence on the petioles, leaflets and inflorescence is generally white, but often with it are reddish and longer hairs which are scattered among the other hairs, except in the articulations of the flowers, pedicels and leaflets, where they appear in tufts.

=Distribution.=--Pennsylvania south to Alabama, west to Iowa and south to the Indian Territory. Found in all parts of Indiana. It is usually a.s.sociated with beech, sugar maple and linn. On account of the poisonous character of its fruit, land owners have almost exterminated it.

From the data at hand it appears that the buckeye was a rare tree in the northern tier of counties. However, as soon as the basin of the Wabash is reached it becomes a frequent to a common tree where beech, sugar maple, and linn are found. In all of our area it prefers a rich moist soil, except in the southern counties it may be found even on the bluffs of streams with the species just named. In the lower Wabash Valley especially in Posey County it was a rare tree, or entirely absent.

[Ill.u.s.tration: Plate 116.

AESCULUS GLABRA Willdenow. Buckeye. ( 1/2.)]

=Remarks.=--In our area the buckeye is the very first tree to put out its leaves. On this account in early Spring it can be easily distinguished in the forest. This character together with its large cl.u.s.ters of flowers which appear early are features which recommend it for shade tree and ornamental planting. The tree has now become so rare in Indiana as to have no economic importance.

=2. aesculus octandra= Marshall. Buckeye. Sweet Buckeye. Plate 117.

Medium to large sized trees with smooth bark which on old trees becomes more or less scaly. This tree closely resembles the preceding from which it can be easily distinguished by the following characters. Its smoother and lighter colored bark; by the entire under surface of the leaves remaining permanently p.u.b.escent; the hairs more or less fulvous; by the included anthers; and by its smooth capsule.

=Distribution.=--Western Pennsylvania, westward along the Ohio to Iowa, south to Georgia and west to Louisiana and Texas. In Indiana it is confined to a few counties along the Ohio River. The records of McCaslin for Jay and Phinney for Delaware counties are doubtless errors in determination. The writer has diligently tried to extend the range of this species in Indiana and has found it only in Dearborn, Jefferson, Clark and Crawford Counties, and in no place more than a mile from the Ohio River. No doubt under favorable situations it found its way to a greater distance from the River. On account of the poisonous character of its fruit, it has been almost exterminated, and only along the precipitous bluffs of the Ohio River are trees yet to be found.

Doubtless its exact range in our area can never be determined. Dr.

Drake[63] minutely described this species and remarks: "This species delights in rich hills, and is seldom seen far from the Ohio River. It frequently arrives at the height of 100 feet and the diameter of four feet."

=Remarks.=--The wood is soft, white and resembles the sap wood of the tulip tree for which wood it is commonly sold. Too rare in Indiana to be of economic importance. Young[64] reported a purple flowered form of buckeye from Jefferson County, but since no specimen was preserved and the size of the plant is not given, it will not be considered here. The form was reported as rare under the name of =aesculus flava= var.

=purpurascens=.

[Ill.u.s.tration: Plate 117.

AESCULUS OCTANDRA Marshall. Sweet Buckeye. ( 1/2.)]

TILIaCEAE. The Linden Family.

TiLIA. The Ba.s.swoods.

Trees with medium sized twigs; leaves alternate, mostly taper-pointed, oblique cordate or truncate at the base, serrate; flowers in axillary or terminal cymes, white or yellow, fragrant, peduncles of the cymes with a leaf-like bract adhering to about half their length; fruit nut-like, woody, 1-celled.

Leaves smooth or nearly so beneath 1 T. glabra.

Leaves densely white or gray p.u.b.escent beneath 2 T. heterophylla.