100 



lobes, the body of the samara plainly transverse-rugose and 

 strongly and densely glandular-punctate between the ridges. 



Vicinity of Eustis, Florida, June, 1894, George V. Nas/i,2iCCOvd- 

 ing to specimen in U. S. Herbarium. Unlike P. trifoliata by its 

 narrow foliage glabrous even when young, and of the same hue 

 on both faces. The samaras also have their marks as unlike 

 those of the northern shrub. 



Ptelea mesochora sp. nov. 



Foliage of less than half the size of that of P. trifoliata, com- 

 monly about one-third as large, glabrous or nearly so, very pale 

 and glaucous beneath ; odd leaflet 2 or 3 inches long, rhombic- 

 ovate, merely acute, not acuminate or even cuspidate, the laterals 

 rather more than half as large, more or less inequilateral : samaras 

 of the largest, commonly i inch long, round-obovate or even 

 slightly obcordate, truncate or subcordate at base, the very broad 

 wing apt to be full and wavy, strongly reticulate, the body oval, 

 small in proportion, excentric, nearer the summit than the base, 

 distinctly rugose, the intervals rather closely punctate. 



Of the region of the upper Mississippi valley and vicinity of 

 Lake Michigan ; the best specimens by Uvibaeli, from Miller's, 

 Indiana. 30 July, 1897; Canton, 111., 1875, /. JVo/fe ; Oquawka, 

 111., Patterson, 1874. Distinct from P. trifoliata by its much 

 smaller foliage and even larger fruits. 



CYTOLOGICAL DIFFERENCES BETWEEN THE PAL- 



MELLA AND FILAMENTOUS FORMS 



OF STIGEOCLONEUM 



By Naohidk Vatsu 



It has long been known that Stigeocloncuin takes two different 

 forms according to environmental conditions. In dry atmosphere 

 the alga is spherical and is known as the palmella form, while 

 in a wet place it becomes filamentous. Four years ago. Dr. B. 

 E. Livingston * succeeded in changing one form into the other 

 simj)ly by transferring the alga from one culture solution to 

 another of different strength. At the suggestion of Dr. Mac- 



* Livingston, 15. V.. On the stimulus wliich causes the change of form in poly- 

 morphic green algae. Bot. (jaz. 30: 289-361. 1900. 



