Juglans californica
Juglans nigra
California black walnut, Southern California black walnut, Southern California walnut
black walnut, noyer noir
with distal edge of leaf scar notched, often shallowly so, glabrescent or bordered by poorly defined velvety patch;
pith brown.
with distal edge of leaf scar notched, usually deeply, not bordered by well-defined band of pubescence;
pith light brown.
15-24 cm;
petiole 2-5 cm.
20-60 cm;
petiole 6.5-14 cm.
(9-)11-15(-17), usually narrowly oblong-elliptic to lance-elliptic, occasionally lanceolate, symmetric or weakly falcate, 4.3-9.5 × 1.6-2.6 cm, margins finely serrate, apex rounded to acute;
surfaces abaxially without tufts of hair in vein axils, abaxially and adaxially glabrous with scales but no hairs, main veins glandular, often sparsely so, leaflets without nonglandular hairs (except for multiradiate hairs early in season);
terminal leaflet well developed.
(9-)15-19(-23), lanceolate or ovate-lanceolate, symmetric or weakly falcate, (3-)6-15 × 1.5-5.5 cm, margins serrate, apex acuminate;
surfaces abaxially with capitate-glandular hairs, simple or 2-rayed fasciculate hairs, and scales scattered over veins and blade, axils of proximal veins with prominent tufts of fasciculate hairs, adaxially glabrous except for scattered capitate-glandular and fasciculate hairs on midrib;
terminal leaflet small or often absent.
1-3, globose, 2.1-3.5 cm, smooth, at first glandular, with scattered scales, soon glabrescent;
nuts depressed-globose, 1.8-2.2(-2.5) cm, shallowly grooved, surface between grooves smooth.
1-2, subglobose to globose, rarely ellipsoid, 3.5-8 cm, warty, with scales and capitate-glandular hairs;
nuts subglobose to globose, rarely ellipsoid, 3-4 cm, very deeply longitudinally grooved, surface between grooves coarsely warty.
buds ovoid to ellipsoid, somewhat flattened, 5-6 mm.
buds ovoid or subglobose, weakly flattened, 8-10 mm.
catkins 5-14 cm;
stamens 15-35 per flower;
pollen sacs 0.6-1 mm.
catkins 5-10 cm;
stamens 17-50 per flower;
pollen sacs 0.8-0.9 mm.
= 32.
Juglans californica
Juglans nigra
Juglans californica is the most distinctive western walnut, but some care must be taken in identifying it. The distinctive leaflet shape of J. californica is occasionally replicated by early-season leaves of other species. Furthermore, J. californica is distinctive in lacking simple and fasciculate hairs on the leaves, but like most other walnuts, multiradiate hairs are normally present on the young vegetative growth (stems, petioles, and midribs) in the spring. The hairs are usually deciduous early in the growing season. They have short (0.1-0.2 mm), crisped rays and are never clustered or especially associated with vein axils. The fasciculate hairs found in all of our other species (except sometimes J. microcarpa) are persistent, have longer (0.3-0.4 mm), straight rays, and are concentrated in clusters abaxially in the axils of the main lateral veins.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Variation of Juglans nigra in central Texas and south-central Oklahoma should be studied; specimens seemingly intermediate between J. nigra and both J. major and J. microcarpa have been seen from this area. E. C. Twisselman (1967) incorrectly reported that J. nigra was locally naturalized in California; his specimens were all J. hindsii (possibly introgressed with J. nigra) and J. californica.
Juglans nigra is frequently cultivated as an ornamental, and the nuts are prized for their strong, distinctive flavor.
Native Americans used Juglans nigra medicinally as a miscellaneous disease remedy, a dermatological aid, and a psychological aid (D. E. Moerman 1986).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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