This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
[Xanthoxylum Mill. Gard. Diet. Ed. 8. 1768] Trees or shrubs with alternate pinnate leaves, the twigs and petioles commonly prickly. Flowers axillary or terminal, cymose, whitish or greenish, mostly small. Sepals 3-5, or none. Petals 3-5, imbricated. Staminate flowers with 3-5 hypogynous stamens. Pistillate flowers with 1-5 distinct pistils, rarely with some stamens. Carpels 2-ovuled. Pods fleshy, 2-valved, 1-2-seeded. Seeds oblong, black and shining. [Greek, yellow-wood.]
About 150 species, natives of temperate and tropical regions. In addition to the following 2 others occur in the Southern States. Type species: Zanthoxylum Clava-Herculis L.
Flowers in small sessile axillary cymes; calyx none.
Flowers in large terminal compound cymes; calyx present.
Xanthoxylum americanum Mill. Gard. Diet. Ed. 8, no. 2. 1768.
A shrub, or small tree, reaching a maximum height of about 250, and a trunk diameter of 6'. Leaves alternate, odd-pinnate, pubescent when young, becoming glabrous or nearly so when old; leaflets 3-11, ovate, opposite, dark green above, lighter beneath, nearly sessile, 1 1/2-2' long, crenulate or entire, acutish; flowers greenish, about 1 1/2" broad, in sessile axillary cymes, borne on the wood of the previous season and appearing before the leaves; pedicels slender; calyx none; petals 4 or 5; pistils 2-5; follicles black, ellipsoid, about 2" long, on short stipes, 1-2-seeded.
In woods and thickets, Quebec to Virginia, especially along the mountains, west to western Ontario, South Dakota, Kansas and Nebraska. Wood soft, light brown; weight per cubic foot 35 lbs. Angelica-tree. Suterberry. April-May.
Z. Clava-Herculis L. Sp. Pl. 270. 1753.
Z. carolinianum Lam. Encycl. 2: 39. 1786.
A small, very prickly tree, with a maximum, height of 45° and trunk diameter of 9', the prickles supported on cushions of cork sometimes 8' broad. Leaves alternate, odd-pinnate, glabrous, shining above, dull beneath; leaflets 5-19, obliquely ovate, nearly sessile, 1 1/2-3 long, acute, crenulate; flowers greenish-white, in large terminal cymes, appearing before the leaves; sepals 4 or 5; petals 4 or 5; pistils 2 or 3; follicles about 2" long, sessile.
Along streams, coast of southern Virginia to Florida, west to Texas and Arkansas. Wood light brown; weight per cubic foot 31 lbs. Hercules'-club. Prickly-yellowwood. Yellow prickly ash. Wild orange. June.
2. PT╚LEA L. Sp. Pl. 118. 1753.
Shrubs or small trees, without prickles, the bark bitter. Leaves 3-5-foliolate, with entire or serrulate leaflets. Flowers greenish white, polygamous, corymbose-paniculate. Calyx 4-5-parted, the lobes imbricated. Petals 4 or 5, much longer than the calyx, also imbricated. Stamens 4 or 5, alternate with the petals; filaments hairy on the inner side, present in the pistillate flowers but the anthers abortive or wanting. Ovary flattened, 2-celled (rarely 3-celled). Fruit a nearly orbicular samara, 2-winged (rarely 3-winged). indehiscent. Cells I-seeded. Seed oblong-ovoid. [Greek, Elm, from the similarity of the fruits.l Three species, natives of the United States and Mexico, the following typical.
Ptelea trifoliata L. Sp. Pl. 118. 1753.
A shrub or small tree, with a maximum height of about 200 and trunk diameter of 6'. Leaves long-petioled, 3-foliolate, pubescent when young, glabrate when old, or sometimes persistently pubescent; leaflets ovate or oval, 2'-5' long, sessile, crenulate, acute or obtuse, the lateral ones somewhat oblique, the terminal one more or less cu-neate at the base; flowers about 5" broad, in terminal compound cymes; odor disagreeable; sepals i" long, obtuse; petals about 3" long, oblong; samara 8"-9" in diameter, the wing membranous and reticulated, emarginate, tipped with the minute persistent style or this finally deciduous.
In woods, Connecticut to Florida, west to southern Ontario, Minnesota, Kansas and Mexico. Consists of many trivially different races. The fruit is bitter and has been used as a substitute for hops. The foliage has an unpleasant odor. Wood light brown; weight per cubic foot 43 lbs. Ague-bark. Quinine-tree. Pickaway-anise. Prairie-grub. Wafer-ash. Swamp-dogwood. Wingseed. June.
Ptelea tomentosa Raf. (P. trifoliata mollis T. & G.) is a very pubescent race, ranging from North Carolina and Georgia to Indiana and Durango.
The common rue, Ruta gravbolens L., a native of Europe, has escaped from cultivation in several localities in our range. It is a heavy-scented herb or partially woody plant and differs from our other representatives of the Rue family in the perfect flowers, the 4-5-lobed ovary and the lobed, several-seeded capsule.