SUB-CLAS8 II. DICOTYLEDONES. 177 



Muencli. in the state. The inner bark of the three species here 

 recognized is yellow, never red. Common in upland woods. 

 Specimens from Canoe creek, Kendallvillc Moneek and Decorah 

 seem to be typical, while others from Ilesper, 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 whicb 

 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 county 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. 



