204 Floristik, Geographie, Systematik etc. 



Picea canadensis B. S. P., the Black Hills spruce is a variety 

 of the common eastern spruce native in the Mountains of South 

 Dakota, it is far superior to the eastern form for planting under 

 adverse conditions. It has been found to be an extremely valuable 

 spruce for planting in the prairie regions. It is drouth-resistant, hardy 

 and easily transplanted ; its timber is not durable in contact with 

 the soil unless treated with preservative. 



Pseudotsuga taxifolia Britton, the Douglas spruce, is a valuable 

 species for general planting in Iowa as it is longer lived than the 

 Norway spruce {Picea excelsa) and produces better timber. It lacks 

 compactness and symmetry of form and the terminal bud is often 

 killed by late frosts in spring causing the stem to be crooked; for 

 these reasons it is unsatisfactory as an ornamental. 



Abies concolor Barry, the silver fir, "is probably the most useful 

 member of the entire fir family for planting in this State. It is 

 entitled to this rank on account of its value for windbrakes and for 

 landscape planting. As an ornamental tree it ranks high and by 

 many is regarded as second only to the Colorado blue spruce 

 [Picea parryajia.Y It is sensitive to drying winds and should be pro- 

 tected when young. It has little value for commercial planting. 



Thuja occidentalisl^., the white cedar, is perfectly hardj' in low, 

 moist situations. It is valuable for windbrakes wherever the soil is 

 moist enough to permit of its growing; it makes valuable posts, 

 poles and repair material. 



Jimipenis virginianal^., the red cedar, "is a hardy thrifty grower 

 and were it not for its relations to the apple rust would have a very 

 high value for windbrake and grove planting in the State." It yields 

 extremely durable posts and its wood is more widely used than any 

 other for lead pencils, pails, tool handles and faucets. It thrives 

 best in dry soils and Supports shade well. As it breeds apple rust 

 {Roestelia) it should not be used for windbrakes near apple orchards. 



Ginkgo biloba L., the Ginkgo, is a deciduous tree but very 

 valuable for city planting as it withstands smoke and gas. The 

 fruits are malodorous and for this reason it is recommended that 

 the male form be propagated by cuttings. It is about as hardy as 

 the hemlock {Tsuga canadensis) and cannot support the winters of 

 northern Iowa except in pro tected localities. W. T. Swingle. 



Greenman, J. M., Studies in the genus Cithavexylum. (Publica- 

 tion 117 - Botanical Series IL p. 185—190 — of the Field Colum- 

 bian Museum. Januari 25. 1907.) 



Descriptions of the following new species: C. Bourgeaniainnn , 

 C. cvassifoliurn , C. Donnell-Smithii , C. Emrickianmn , C. hexangidare , 

 C. Kerberi, C. macrodeniinn , C. puncftjatum, C. reciirvatum and 

 C. Schottii. Trelease. 



Heller, A. A., New western plants. (Muhlenbergia. III. p. 10-12. 

 Jan. 30. 1907.) 



Cakile californica and Ribes Suksdorfii. Trelease. 



House, H. D., New species of Ipomoea from Mexico and Central 

 America. (Muhlenbergia. III. p. 37—46. pl. 1—3. March 1907.) 



Contains the following new names: Ipomoea domingensis {Con- 



