58 LEAFLETS. 



Known only from western Ontario, near Wingham, where 

 it was collected by J. A. Morton, 13 July, 1890, the specimens 

 in Herb. Canad. Geol. Survey. 



Thalictrum altissimum. Plants very tall, often 6 feet 

 high and even more, the stems erect, rigid, manifestly angled, 

 dark with minute purple dots, glabrous to the summit, and 

 even as to the branches of the panicle and pedicels of the 

 flowers : basal leaves a foot in diameter exclusive of the petiole, 

 this glabrous, but the ultimate petiolules plainly hirtellous : 

 leaflets firm, deep green, smooth and glabrous above, beneath 

 yellow-green and, especially along the veins, softly hirtellous, 

 the margins revolute, terminals an inch long, round-obovate 

 or subcuneate-obovate, either subcordate or nearly truncate at 

 base, 3-lobed at apex, the middle lobe thrice as large as the 

 laterals, all lobes conspicuously cuspidate-mucronate, lateral 

 leaflets either oval and entire, or some of them broader and 

 with one lateral lobe or tooth : sepals of staminate plant obo- 

 vate, obtuse, white, of the fertile plant more elongated, acute : 

 filaments all clavellate and erect ; anthers oblong, very obtuse : 

 achenes black, small for the plant, sharply ribbed, tipped with 

 the persistent straight style. 



This is the common summer-flowering white-stamened 

 meadow rue of river banks and other wet places in Virginia, 

 Maryland and northward into Pennsylvania. It flowers along 

 the banks of the Potomac all through July, and its fruit ripens 

 in August, and is black as soon as ripe. Both the leaves, 

 leaflets, flowers and fruits are remarkably small, the plant 

 itself among the very largest of its genus, and of a lax and 

 poor aspect on account of the wide spread of the nearly naked 

 branches, these floriferous at the ends only. They are nearly 

 divaricate ; and the lax open panicle itself often measures two 

 feet or more from base to summit, yet, from its laxity and 

 openness, is ill defined as an inflorescence. In this particular 

 our plant of these Middle States is very unlike all far 

 northern and northwestern and western plants that have, with 

 this, been mixed up from early times under the name of 

 T. Cornuti, and more recently under that of T. polygamum. 



