176 



leaf}- to the top; the leaves all narrowly linear from a broad 

 base, 3-6 cm. long, about 5 mm. wide, the upper shorter, equaling 

 or surpassing the inflorescence, appressed pubescent on both 

 surfaces, the midrib prominent; flowers many in close clusters 

 on ascending peduncles, the pedicels hirsute pubescent, the calyx 

 3-3.5 mm. long, divided to very near the base, the lobes narrowly 

 linear, glabrous except the ciliate margins, the corolla about 10 

 mm. long, the tube and limb about equal in length. 



Mertensia media belongs to the Lanceolateae, and, following 

 Dr. Rydberg's Key in the Flora of Colorado, its characters lead 

 to M. lateriflora Greene or M. amoena A. Nelson; but it is quite 

 a difTerent plant, noticeably in the pubescence. M. lateriflora 

 has "the whole plant canescently silky-strigose," ahd M. amoena 

 is much the same. It is a taller plant than M. amoena, the leaves 

 are longer and more pointed, the calyx lobes are narrower and 

 less ciliate. In general appearance it closely resembles M. 

 lanceolata (Pursh) DC. Collected at Palmer Lake, El Paso 

 County, Colorado, May 24, 1913; no. 4882. 

 Windsor, Colo. 



SOME EFFECTS OF EXCESSIVE HEAT IN NORTHERN 



MICHIGAN* 



By Henry All.\n Gleason 



During the last week of July, 191 7, a heat wave of unprec- 

 edented intensity spread over the region of the Great Lakes. 

 At numerous stations of the Weather Bureau temperatures in 

 excess of 100° F. were recorded. At the biological station of the 

 L^niversit}" of Michigan, located seventeen miles south of the 

 Straits of Mackinac, all previous records for high temperatures 

 were passed. On July 29, the temperature was above 90° for 

 over nine hours, and reached a maximum of 101°. The following 

 day a maximum of 93° was recorded. On July 31, the tempera- 

 ture was above 100° for over five hours, with a maximum of 

 104°, and above 90° for eleven hours. During these same days 

 the minimum was also unusually high, remaining above 80° for 

 three and a half da^'s continuously. 



* Paper No. i66 from the Botanical Laboratory of the Universitj* of Michigan. 



