160 IOWA ACADEMY OF SCIENCES. 



THE JUGLANDACEAE OF IOWA. 



BY T. J. AND M. F. L. FITZPATRICK. 



Jiiglcnidaceae Lindl. Nat. Syst. Ed. 2, 180, 1836. 



WALNUT FAMILY. 



The walnut family comprises six genera and about 85 

 species. Only two genera occur in Iowa, namely, Juglans 

 (Walnut) and Hicoria (Hickory), and these two genera are 

 represented by two and five species respectively. From an 

 economic point of view the species are valuable and con- 

 sequently have been largely utilized until but few speci- 

 mens of the older forest remain. The younger growth is 

 hardy and will, if spared, eventually yield fair returns. 



In general terms the walnut family includes trees with 

 alternate pinnate exstipulate (sometimes stipulate in the 

 bud) leaves and monoecious bracteolate flowers. The stam- 

 inate flowers are in long-drooping aments with an irreg- 

 ular calyx adnate to the bract and three to many stamens. 

 Pistillate flowers are solitary or clustered with a regular 3-5- 

 lobed calyx adherent to the partially 2-4-celled 1-ovuled 

 ovary; styles 2; fruit a drupe with a fibrous or woody husk 

 and a large 2-4-lobed seed. 



Juglans. Husk indeliiscent; nut furrowed. 



Hicoria. Husk 4-valved, dehiscent; nut smooth or angled. 



Juglans nigra L. Sp. PI. 997. 1758. Black Walnut. A 

 tree, 50-100 feet or more high, with furrowed strong- 

 scented brown bark, wood purplish brown, pith in trans- 

 verse plates, young twigs and petioles puberulent, becom- 

 ing glabrous with age, and odd-pinnate leaves. Leaflets 

 nearly sessile, serrate, 11-23, ovate-lanceolate, acuminate, 

 mostly glabrous above, pubescent beneath, base sub-cordate 

 or unequal; fruit spherical, 4-celled at the base. 



