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The Trees of Great Britain and Ireland
Key to the Species of Juglans in Cultivation
I. Leaflets not serrate; usually entire or sinuate (Plate 73).
- 1. Juglans regia, Linnæus. Bosnia and Greece, through W. Asia and Himalayas to N. China.
- Leaf-scars deeply notched without a pubescent band on their upper edge. Leaflets 7 to 9, glabrous beneath except for inconspicuous axil tufts.
II. Leaflets serrate. Leaf-scars without a pubescent band on their upper edge.
* Leaflets glabrous beneath, except for the axil tufts.
- 2. Juglans regia x nigra. Two forms: Juglans Vilmoriniana, Carriére, and Juglans pyriformis, Carrière.
- Leaflets 11 to 13, with fine shallow serrations.
** Leaflets pubescent beneath.
- 3. Juglans rupestris, Engelmann. Arizona, Texas, New Mexico, Mexico.
- Leaflets small, 7 to 15, ovate or lanceolate, never oblong, green beneath. Young shoots glandular-pubescent.
- 4. Juglans nigra, Linnæus. Canada and United States, east of the Rocky Mountains.
- Leaflets large, 15 to 19, ovate-oblong with long-acuminate apex, pale beneath. Young shoots glandular-pubescent.
- 5. Juglans stenocarpa, Maximowicz. Manchuria.
- Leaflets large, 11 to 13; all oblong, except the terminal one which is broadly obovate, pale beneath. Young shoots glabrous.
III. Leaflets serrate. Leaf-scars with a transverse pubescent band on their upper edge.
- 6. Juglans cinerea, Linnæus. Canada and United States, east of the Rocky Mountains.
- Leaf-scars semicircular, the upper edge straight and scarcely notched. Leaflets, 11 to 13, oblong; serrations fine and directed outwards.
- 7. Juglans Sieboldiana,[1] Maximowicz. Japan, Saghalien.
- Leaf-scars obcordate, 3-lobed, notched above. Leaflets, 13 to 15, oblong; serrations shallow, irregular, directed forwards; base rounded and unequal.
- 8. Juglans mandshurica,[1] Maximowicz. Manchuria, Korea, China.
- Leaflets and leaf-scars practically indistinguishable from those of the last species, though the leaflets are usually longer-acuminate. Fruit, however, remarkably distinct. See detailed description.
- 9. Juglans cordiformis,[1] Maximowicz. Japan.
- Leaf-scars and leaflets closely resembling those of J. Sieboldiana, the leaflets however, fewer (11 to 13) and with a cordate base.
