1910] The Ottawa Naturalist. 139 



almost naked, which impelled me to halt and inspect them more 

 closely. There were plenty of clusters of fruit remaining in fair 

 condition from the autumn before. The drupelets were those of 

 the group of Rhus glabra; and this was a surprise, because the 

 first glance at the branches had convinced m^e beyond possibility 

 of doubt that the colony was of the R. typhina group; not that 

 they manifested that dense velvety, or rather plushy indument 

 like that of the horns of stags when the horns are newly grown. 

 There are Rhus typhina allies, unquestionably such to all who 

 know them, that have no trace of the velvet or plush on their 

 branches at any time. These are conditions of which the 

 botanists who write the descriptive manuals know nothing. The 

 book does not yet exist in which the most fundamental distinc- 

 tions between these exceedingly common shrubs, those of the 

 glabra type and those of the typhina type have been given. What 

 the most essential characters of the two groups are, I proceed to 

 state; and first, those marking the typhina group. The young 

 branches are cylindrical, or terete, to use the good botanical term, 

 which means that the cross section is in outline a circle; also the 

 bark of such young branches is of a deep or dark green, without 

 trace of bloom or pallor. In every form or phase or distinct 

 species of the glabra alliance such young branches are not only 

 pale or whitish with bloom, they are never cylindric or terete, 

 but always plainly angled, their cross sections never circular, 

 always angular, more or less definitely and acutely so. By such 

 clear and definite notes as these may the botanist out of doors 

 distinguish betv-een these two types of sumach even in mid- 

 winter; and both tvpes are common over an area that embraces 

 almost all of North America east of the Rocky Mountains. And 

 the points of difference here emphasized have not been known 

 to the writers of our manuals sitting in the herbarium, although 

 herbarium specimens exhibit them. 



I shall have more to say concerning the sumachs of West- 

 ern Ontario by and by. 



This perhaps more distinctively southwestern part of the 

 great province, as I traversed it from Sarnia near the southern 

 point of Lake Huron to Hamilton on Lake Ontario, and as I 

 have walked some scores of miles of it in pursuit of botanical 

 knowledge, has to me the appearance of what may have been 

 from the first a gentlv undulating prairie country broken into 

 sections of small extent by many woodland-belted rivers and 

 their numerous lesser triVjutaries. 



Across the prairie looking eastward from Strathroy I noted 

 as at the probable distance of a mile and more a stretch of timber, 

 where I supposed I should find a water-course of some kind, and 

 on the wooded hills above one special desideratum, Thahctrum 



