Week 17 – Monday Announcements: No lecture WED – LAB EXAM, finish up lecture Friday – come with questions… Cannabaceae s.l. Woody members of Cannabaceae (which is traditionally restricted to Cannabis and Humulus) at one time were included in the Ulmaceae (subfamily Celtidoidaea) or separate family (Celtidaceae), now found to be most closely related to traditional Cannabaceae. Can be distinguished from Ulmaceae s.s. by: • Secondary veins not terminating in the teeth, but rather forming a series of loops • Fleshy fruits (drupes) as opposed to samaras (Drupe = fleshy indehiscent fruit with a stony endocarp surrounding a usually single seed - as in a peach or cherry) • Series of other characters including secondary chemistry, pollen architecture, and base chromosome number Celtis reticulata – netleaf hackberry A small scraggly tree or large shrub widely distributed throughout the west but never abundant. Occurs in river canyons of the Inland northwest including, the Snake, Salmon and Columbia. Also occurs on bluffs and semi-desert plains. Has been used for posts, furniture, fuel and barrels. May reach 7-20' (30-40’ max) tall and 1-2' diameter at maturity. Vegetative Features: • Leaves are simple, alternate, decisuous, 2-4" long, ovate with conspicuous net-like (reticulate) venation patterns and margins with widely spaced teeth. • Twigs with chambered pith • Bark is tan to gray with conspicuous warting on younger trees, but becomes corky and ridged on older trees. Reproductive Features: • Monoecious, small flowers borne in leaf axils – inconspicuous and wind pollinated. • Fruit is a drupe about 1/4-3/8" long with sweet flesh. 130 (Celtis occidentalis – hackberry) Widely distributed in the eastern United States from the southern New England States through central New York west in southern Ontario to North and South Dakota. Larger tree than western counterpart – up to 60 ft. tall. Vegetative Features: • Leaves are simple, alternate, decisuous, 2-5" long, ovate with conspicuous net-like (reticulate) venation patterns and a serrate margin. • Twigs with chambered pith • Bark is tan to gray with conspicuous warting on younger trees, but becomes corky and ridged on older trees. Reproductive Features: • Monoecious, small flowers borne in leaf axils – inconspicuous and wind pollinated. • Fruit is a drupe about 1/4-3/8" long with sweet flesh. 131 Moraceae – mulberry or fig family Ca. 50 genera and 1500 species of trees, shrubs, vines. Primarily distributed in the warmer regions of the world, but with several temperate species. Ficus (figs) is the most diverse genus with over 800 species – mostly tropical and shows an amazing array of growth forms from epiphytes, vines, shrubs, small trees, shrubs etc. to large trees. Closely related to Ulmaceae and Cannabaceae and has similar small, mostly wind-pollinated flowers. Ficus is an exception and has specialized, coevolved fig-wasp pollinators. Vegetatively they all have milky latex distributed throughout the plant. 8 genera are found in North America – they are small – medium sized trees commonly used ornamentally. Tropical trees are important for timber, edible fruits (figs), paper fibers, and dyes. Morus alba – white mulberry Of the 10 species of Morus – 2 are native to US and 2 others have naturalized – we will look at one of the naturalized species, but very similar to natives… Native to China – introduced in the in early 1600’s to try to establish a silkworm industry – didn’t work. Naturalized throughout the US and southern Ontario and has become weedy in disturbed areas – particularly at the urban-wild interface. A small tree up to 40 feet tall, branches low and develops a wide spreading crown Vegetative features: • Leaves simple, alternate, deciduous, stipulate, roughly orbicular in shape, 3 to 6 inches long with a serrate margin, often irregularly lobed, smooth above. • Milky latex evident in broken petiole of young leaves. • Bark orange-brown with lenticels when young, becoming gray with long narrow irregular ridges. Reproductive features: • Normally dioecious – flowers small, green catkins, male flowers narrow, 1 to 2 inches long; female flowers plump, 1 inch long • Fruit resembling blackberries, cylindrical, 1 to 1 1/4 inch long, fleshy multiple of drupes, pale pink to dark red, not as juicy as red mulberry (Morus rubra) 132 Maclura pomifera – Osage orange Maclurais a monotypic genus. The single species has a very restricted native range – southern Arkansas, southern Oklahoma, and northeastern Texas, but is widely planted throughout the US and Canada as an ornamental. The wood is among the most decay resistant in North America and has a characteristic bright yellow-orange color. Attempts to plant only males ornamentally because of characteristic large, heavy, fruit – but fruit is really the most interesting part! A medium sized tree with a short trunk. The crown is irregular, with stiff, spiny branches. Vegetative features: • Leaves alternate, simple, pinnately veined, 2 to 5 inches long, oblong to ovate with an acuminate tip, margins entire, upper surface shiny. • Twigs are armed with stout, unbranched thorns at each leaf scar. • A milky sap is exuded when cut. • Bark orange-brown, developing scaly ridges with irregular furrows. Reproductive features: • Dioecious; flowers inconspicuous. Females is borne in dense, globose, clusters. Male borne in subglobose racemes. • Fruit a large, round multiple of drupes 4 to 5 inches in diameter, with a very distinctive citrus smell; the outer surface looks like "brains"; when crushed, a white, milky juice is exuded. Anacardiaceae - the cashew family Includes approximately 70 genera and 875 species of trees and shrubs primarily in the warmer regions of the world. Many species are commercially important; Anacardium occidentale, cashews; Pistacia vera, pistachios; and Mangifera indica, mangos. Others of the genus Toxicodendron cause severe contact dermatitis. We’ll look at two genera – Rhus (sumacs) and Toxicodendron (poison ivys) - Rhus and Toxicodendron have often been confused – some botanists treating as one genus – but, fruits of Rhus are glandular pubescent and red, fruits of Toxicodendron are glabrous and greenish-white. In addition the resins of Rhus are not poisonous while Toxicodendron contains urushiol and causes contact dermatitis. All members of Anacardiaceae that have cream colored, glabrous drupes and the oil urushiol that causes contact dermatitis in humans were reclassified into the genus Toxicodendron about thirty years ago. 133 Rhus glabra - smooth sumac A shrub or small tree primarily of the eastern US but scattered widely in the west as well. Occupies open woodlands, clearings, roadsides and waste places. May reach 4-15' tall and 1-4" diameter. Vegetative Features: • Usually a many-trunked small tree or large shrub. • Deciduous, alternately arranged pinnately compound leaves are 1-2' long with 11-31 lanceolate leaflets that have serrate margins. Turn red in fall. • Stems have large pithy core. Limbs are glabrous and glaucescent. • They have milky sap and small, scaleless buds. • Bark is gray-brown and smooth, but becomes scaly on older plants. Reproductive Features: • Dioecious, female flowers are small, white and are borne in terminal panicles. • Fruits are 1/8" long, hairy, red drupes that may remain on the tree for several months. Rhus typhina - smooth sumac A shrub or small tree primarily of the eastern US but scattered widely in the west as well. Occupies open woodlands, clearings, roadsides and waste places. May reach 25' tall and 1-4" diameter. Branches repeatedly and widely forked crown. Vegetative Features: • Usually a many-trunked small tree or large shrub. • Deciduous, alternately arranged pinnately compound leaves are 1-2' long with 11-31 lanceolate leaflets that have serrate margins - rachis pubescent. Turn red in fall. • Stems have large pithy core. Limbs are densely pubescent – resembling deer antlers in velvet. • They have milky sap and small, scaleless buds covered in soft hairs. • Remaining pubescent for several years, turning gray-brown and much later becoming a bit scaly. Reproductive Features: • Dioecious, female flowers are small, yellow-green and are borne in terminal panicles. • Fruits are 1/8" long, hairy, red drupes that may remain on the tree for several months. 134 Toxicodendron radicans – poison-ivy A catch-all for several taxonomically troublesome and highly variable species. Toxicodendron: Includes T. vernix, poison sumac; T. diversilobum, the Pacific poison oak, T. radicans, the climbing poison-ivy. Collectively they occupy much of the US except major mountain ranges and deserts of the west. Contact dermatitis is caused by the oil urushiol which initiates an autoimmune response. Some people appear to be resistant but become sensitive with repeated exposures. Severe rashes requiring hospitalization and treatment with steroids are common. Deaths have been recorded. Vegetative Features: • All are deciduous with compound leaves. T. vernix has pinnately compound leaves with 5-13 leaflets (like Rhus) all others have trifoliate leaves although some will occasionally have 5 leaflets. Leaflets of three leave them be. • May be present as a low (6 to 18 inches), spreading "carpet" on the forest floor, as a climbing vine, or as a bush, or small shrub (T. vernix). Reproductive Features: • Monoecious – small, yellowish-green flowers arranged in a panicle • Fruit a cream-colored drupe, ¼ inch in diameter arranged in panicle. 135 Elaeagnaceae – the oleaster family Includes 3 genera and approximately 45 species