Leafsnap, an on-line
pictorial database of tree identification by species.
Vascular Plant Image Library (Ulmaceae)
Dendrology at Virginia
Plants USDA - Topics
Texas Native Plants Database
International Plant Names Index
Tree ID - The National Arbor Day
Tree Species Distribution Maps for North America [.pdf and .arcinfo files]
Vascular Plants - A virtual herbarium; A project of the N.Y. Botanical Gardens
Silvics of North America:
Our State Tree
(Juglandaceae Carya illinoinensis ) Adopted in 1919. The pecan is
a large tree native to North America. It bears sweet edible nuts,
deep brown in color, that range from 1 to 2 inches in length.
The mature pecan tree is usually 70 to 100 feet tall, as many are
in local parks, but can grow as tall as 150 feet and higher in the
open field. The native
pecan trees shown in our database are estimated to be over 150 years
old. Their trunks can grow to more than three feet in diameter!
Texas is the largest producer of native pecans, and is second
only to Georgia in the production of hybrid (orchard grown)
varieties. The pecan became the Texas state tree by act of the
Texas Legislature in 1919. Governor James Hogg favored the tree so
much that he requested that one be planted at his gravesite.
Chapter 97 (Senate Bill No. 317), 36th Legislature, Regular
Session (1919) p. 234 Pecan (Carya illinoensis) is one of the
better-known pecan-hickories. It is also called sweet pecan and in
its range where Spanish is spoken, nogal morado or nuez
encarcelada. The early settlers who came to America found the
growing over wide areas. These native pecans were and continue to
be highly valued as sources of new varieties and as stock for
selected clones. Besides the commercial edible nut that it
produces, the pecan provides food for many varieties of wildlife. Pecans are an
excellent multipurpose tree for the home landscape by providing a
source of nuts, furniture-grade wood and landscaping esthetic value.
See the link for Glossary in the footer.
Leaf: Alternate, pinnately compound with 9 to 15 finely
serrate and often curved leaflets, 12 to 18 inches long.
Flower: Male flowers in hanging, yellow-green catkins,
often in pairs of three (4 to 5 inches long). Females are small
and yellowish green, 4-angled.
Fruit: Large, oblong, brown, splotched with black, thin
shelled nuts, 1 ½ to 2 inches long, husks are thin, usually occur
in clusters on trees. Mature in September and October.
Twig: Moderately stout, light brown, fuzzy particularly,
when young; leaf scars large and three lobed; buds are yellowish
brown to brown, hairy, terminal buds ¼ to ½ inch long.
Bark: Smooth when young, becoming narrowly fissured into
thin broken strips, often scaly.
Form: A large tree (can reach heights well over 100
feet) with spreading crown when in the open.
Pecan Taxonomic Hierarchy
Kingdom Plantae -- Plants
Subkingdom Tracheobionta -- Vascular
Superdivision Spermatophyta -- Seed plants
Magnoliophyta -- Flowering plants
Class Magnoliopsida --
Subclass Hamamelidae – Order Juglandales – Family
Juglandaceae – Walnut family
Genus Carya Nutt. – hickory
Carya illinoinensis (Wangenh.) K. Koch – pecan
Source: Dendrology at Virginia Tech U.S. Department of