SUB-CLASS II. DICOTYLEDONES. 177 
Muench. in the state. The inner bark of the three species here 
recognized is yellow, never red. Common in upland woods. 
Specimens from Canoe creek, Kendallville, Moneek and Decorah 
seem to be typical, while others from Hesper, Moneek, Free- 
port, Calmar and Ft. Atkinson approach Q. velutina in the 
character of the acorn. The series is interesting, and needs 
further study. 
Quercus borealis Michx. (Q. coccinea var. ambigua Gray.) 
Gray Oak. Specimens which appear to be typical, and which 
agree exactly with Engelmann’s specimens labelled Q. ambigua 
in the herbarium of the St. Louis Botanical Garden, were col- 
lected at Hesper and Sattre, and observed throughout the 
northeastern part of the courty in upland groves remote from 
streams, and frequently in the company of the preceding species. 
The leaves are like the moderately lobed, broad, typical leaves 
of Q. rubra, while the acorns resemble those of Q. velutina, but 
the scales of the cup are appressed. The bark is comparatively 
smooth, thin and very brittle, and the general aspect of the 
tree is different from that of any other Iowa oak. Sargent 
refers Q. ambigua (which is the same as this species) to Q. 
rubra, but judging from the specimens here reported this is 
certainly an error. 
Quercus velutina Lam. (Q. coccinea var. tinctoria Gray.) 
Yellow Oak; Black Oak. This species is rather common in 
the southern part of the county. It was obtained at Decorah, 
and observed at Ft. Atkinson, etc. The species is replaced 
northward by the two preceding species. 
Quercus alba L. White Oak. Common in upland groves and 
deep woods, especially near streams. Decorah (Savage), 
Bluffton, Highlandville. Also observed at Hesper, Canoe 
creek, both forks of Bear creek, Kendallville, Moneek and Ft. 
Atkinson. Our -most valuable forest tree. 
Quercus macrocarpa Michx: Bur Oak. Common in upland 
woods. Collected at Decorah and Calmar, and observed in all 
parts of the county where collections were made. This tree, 
is very variable in the size and form of the leaves and acorns, 
according to habitat. 
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