The document provides descriptions of 6 woody plant species in the Populus genus: Populus alba (white poplar), Populus angustifolia (narrowleaf cottonwood), Populus deltoides/sargentii (plains cottonwood), Populus nigra 'Italica' (Lombardy poplar), Populus tremuloides (quaking aspen), and Populus x acuminata (lanceleaf cottonwood). Each species description includes key identifying features such as leaf shape and margins, bud and bark characteristics, growth form, and flowering details. The document also provides images of diagnostic characteristics to aid in visual identification of the Populus species.

1. Woody Plants #6 Populus alba Populus angustifolia Populus deltoides/sargentii Populus nigra ‘Italica’ Populus tremuloides Populus x acuminata White Poplar Narrowleaf Cottonwood Plains Cottonwood Lombardy Poplar Quaking Aspen Lanceleaf Cottonwood

2. Populus alba White Poplar

3. Populus alba

6. ID Populus alba small, imbricate buds appressed light chestnut brown buds showy, white bark pubescent and white leaf undersides Unusual 5 lobed leaf for a populus coarsely toothed leaf margins catkins

7. Populus angustifolia Narrowleaf Cottonwood Mistaken for a willow because of narrow leaves Predominant tree in the San Juans and So.west Colorado Striking Fall Color

10. Populus deltoides/sargentii Plains Cottonwood

11. Populus deltoides

16. Populus deltoides/sargentii Hardiness Zones: 2 to 7 Height: 80 ft Spread: 40 ft Form: rounded Type: deciduous tree Annual Growth Rate: more than 18 inches Comments: Sargent poplar is pyramidal when young but becomes rounded with age. The tree is found near rivers and may be used in wet soils. Poplars are problem-prone plants that require more care than other trees.

17. Populus deltoides/sargentii Leaf: Alternate, simple, pinnately veined 3-6”, triangular. Deltoid shape Petiole flattened and glands at the top of the petiole Flower: male and female catkins Fruit: Cottony seeds ¼” long in a capsule that opens Buds, slender and very pointed

18. Populus deltoides/sargentii buds are resinous and pine-scented winged stems showy furrowed bark toothed margins yellow catkins

20. Largest Plains Cottonwood in Hygiene, CO

22. Male Female

24. Populus nigra ‘Italica’ Lombardy Poplar Leaf: Alternate, simple, broadly deltoid, 2-4 in, finely serrate-crenate, straight across the base, flattened petiole shiny dark green above, paler below Flower: only male trees, slender, reddish to yellow-green catkins 2-3 in long; in spring before leaves Fruit: no fruit in ‘Italica’

25. Populus nigra ‘Italica’ small, imbricate, appressed buds; reddish brown Deltoid leaf shape serrate leaf margins bright green leaf color red catkins columnar growth habit

30. Populus x acuminata Lanceleaf Cottonwood Cross between Populus angustifolia x P. deltoides Full sun Sharply pointed leaves up to 4 inches long Alternate, simple, dentated, narrow tip, glossy Pyramidal form Yellow fall color

32. Populus x acuminata

35. Populus tremuloides Aspen 110 years old 90 ft tall

38. Female Male

40. ID Populus tremuloides terminal, imbricate, conical, sharp-pointed buds buds are resinous and reddish brown narrow, conical habit finely, serrated leaf margins slender, reddish, brown twigs No corky bark

41. ID from Photographs

42. ID Entire Tree

46. ID Leaves

53. ID Fruit

55. ID Flower

56. Male Female

57. ID Bark