IOWA ACADEMY OF SCIENCES. 
169 1 
'pecan and H. minima. (C. olioceformis and C. amara.y 
Barnes, Reppert, and Miller in their Flora of Scott and 
Muscatine counties mention two hybrids as occurring in 
the big timber near Muscatine, namely, Cary a olivceformis 
X C. tomentosa and Carya olivceformis X C. amara. 
BETULACEAE OF IOWA. 
BY T. J. AND M. F. L. FITZPATRICK.’ 
BETULACEAE Agardh, Aphor. 208, 1825. 
THE BIRCH FAMILY. 
The Birch family as now understood, comprises six 
genera and about seventy-live species, mostly natives of 
the northern hemisphere. Some authors include this 
family with the Oak; or Beech family under the name of 
Cupuliferae. The chief distinction is the arrangement of 
the pistillate flowers. The Birch family has the pistillate 
flowers in aments while the Oak family has the pistillate 
flowers subtended by an involucre which becomes a bur or 
cup in fruit. 
The family may be briefly characterized as trees or 
shrubs, with alternate petioled simple leaves, deciduous 
stipules, and monoecious flowers. The sterile flowers are 
in oblong or subglobose pendulous aments; stamens 2—10, 
inserted at the base of the regular or scale-like calyx; 
anthers 2-celled, the cells adnate or distinct. Pistillate 
aments erect, spreading or drooping, spicate or capitate; 
calyx, adnate to the ovary, sometimes wanting. Ovary 
1- 2-celled, with 1-2 ovules in each cell; style 2-cleft or 
2- parted. Fruit a one-celled, one-seeded nut, solitary or 
clustered, and usually involucrate. In most cases the fruits 
should be collected for certain identification. 
Iowa has within its borders only seven species distrib- 
uted through five genera. Only one species, the hazel-nut, 
is distributed throughout the state. .All the others have a 
