Distribution: North temperate with southern extensions into both Old and New World subtropics at higher elevations - 2 genera with 12 species in Texas.
Floral structure:

Significant features:
Common and important elements of North temperate deciduous forests world
wide, including Walnut (Juglans) and Hickory (Carya)
species. Distinctive by their 'amentiferous' floral structures combined
with alternate, pinnately compound leaves that are often aromatic
and a distinctive fruiting structure. The true fruit is a nut, but
this is enclosed in an indehiscent, leathery or fibrous 'husk' derived
from the involucre. The mature
seed contains a fully developed embryo (convoluted or contorted contents
of a walnut or pecan represent its cotyledons. Thus, a high
protein/oil food product for both wildlife (ecological importance) and
humans (economic importance - English walnut = Juglans regia
and pecan
= Carya illinoensis).
Carya texensis - staminate inflorescence at
anthesis
Carya texensis - pistillate inflorescence
at anthesis
Juglans regia - overview from Kohler's
Medicinal Plants
More information on the Juglandaceae