Flowering Plants: Smartweeds to Hazelnuts

Platanaceae—Sycamore Family

Liqllidamba.· I 109 1. Liquidambar styraciflua L. Sp. PI. 999. 1753. Figs. 55, 56. Tree to 35 m tall, with a trunk up to 1. 5 m in diameter, the branches forming a pyramidal crown; bark gray, becoming scaly; winter buds ovoid, up to 6 mm long, with many orange-brown scales; twigs reddish -brown at first, sometimes developing corky wings, often in an irregular pattern; leaves palmately 5- to 7-lobed, serrate, truncate or more or less subcordate at base, green on both sides, glabrous on the upper surface, glabrous except for tufts of hairs in the axils of the veins below, up to 15 cm across, with slender, usually glabrous petioles up to 15 em long; staminate flowers in globose heads up to 6 mm in diameter, with several heads in a terminal raceme, the flowers subtended by hairy bracts; pistillate flowers in a solitary, globose head up to 12 mm in diameter, borne on long pendulous peduncles; fruit a globose head of ripened carpels, the head up to 3 em in diameter; seeds light brown, winged, up to 1 em long. ~--'-4-'r+-'- COMMON NAMES: Sweet Gum; Red Gum. HABITAT: Low woods. RANGE: Connecticut and New York, across Ohio to southern Illinois and southeastern Missouri, south to Texas and Florida; Mexico. ILLINOIS DISTRIBUTION: Confined to the southern ,--'---""= one-half of the state. Sweet gum is one of the most beautiful trees native to Illinois. The wide variety ofcolors that the leaves show in the autumn is outstanding. The leaves, when crushed, yield a pleasant fragrance. The close-grained, red-brown wood is valuable for cabinetmaking . The wood produces a fragrant, reddish resin. Although each fruiting head forms hundreds of seeds, most of the seeds are abortive and sawdustlike. Some specimens produce heavy, corky wings on the branchlets, while other specimens are devoid of the wings. The flowers of the sweet gum are produced from April to early May. PLATANACEAE-SYCAMORE FAMILY Only the following genus comprises the family. 110 I SMARTWEEDS TO HAZELNUTS 55. Liquidambar styraciflua (Sweet Gum; Red Gum). a. Leafy branch, x 1. b. Leaf, x 1 . c. Winter twig and bud, x 2 . d. Fruiting head, x 3. e. Seed, x 8. Platanus / III h 56. Liquidambar styracifltta (Sweet Gum; Red Gum). f. Twig with corky wings, XL g. Flowering branch, X 1. h. Flower, X 20. 1. Platanus L. -Sycamore; Plane Tree Monoecious trees with thick, furrowed bark separating from branches and younger trunk in large plates; leaves simple, alternate , broad and lobed with sheathing, persistent stipules; staminate flowers in heads on axillary peduncles; pistillate flowers in heads on long, terminal peduncles; fruit a nutlet, light brown, obovoid, 1seeded with persistent styles. Three species of this genus are found in the United States. Platanus occidentalis L. occurs in the eastern forests; P. racemosa Nutt. and P. wrightii S. Wats. occur in the western United States. All resemble each other in having broad, lobed leaves with petioles inflated at the base and encircling the bud, and in scaly deciduous bark. Only the following species occurs in Illinois. 1. Platanus occidentalis L. Sp. PI. 999· 1753· Fig. 57. Platanus glabrata Fern. Proc. Am. Acad. Arts & Sci. 36:493. 190 1. Platanus occidentalis L. var. glabrata (Fern.) Sarg. Bot. Gaz. 67:2 30 . 1919. Platanus occidentalis L. var. attenuata Sarg. Man. Trees N. Am. 372. 1922. 112 / SMARTWEEDS TO HAZELNUTS 57. Platanus occidentalis (Sycamore; Plane Tree). a. Leafy branch, with stipules, X 1b . Winter twig and buds, X 2. c. Stamen, X 20. d. Ovary, X 20. e. Fruiting head, X 1'12. Platanus / 113 Large trees to 30 m tall, trunk up to 3 m in diameter, the crown broad; bark scaly, separating from the young trunk and branches, light brown; twigs terete, becoming glabrous, orange-brown in the first year, light brown by the second; buds light brown, ovoid, acute, up to 1 cm long; leaves broadly ovate, with 3-5 sharppointed , shallow lobes, glabrous or nearly so at maturity; petioles up to 20 em long, terete, puberulent, inflated at the base and enclosing the bud; staminate flowers with 3-6 stamens, 3-6 sepals, 3-6 petals; pistillate flowers with a calyx of 3~6 parts, 3-6 petals, and 1 or rarely 2 superior ovaries; fruit a nutlet, obovate, light brown, in heads of drooping peduncles, subtended by numerous...