138 



Inner bark mucilaginous; leaves very rough above; flowers 



nearly sessile; fruit not oiliate 1 U. fulva. 



Inner bark not mucilaginous; leaves smooth or somewhat rough 

 above; flowers on slender pedioils; fruit eiliate. 

 Branches without corkj- wings; sides of samara glabrous.... 2 U. americana. 

 Branches (at least some of them) with corky wings; at least 

 one side of the samara pubescent. 

 Bud.s ovate, not t^^^ce as long as wide, olituse, or short- 

 pointed, dark brown; scales pubescent and eiliate; 

 leaves usually not twice as long as wide, base of 



petiole glabrous beneath; calyx lobes 7-9 3 U. Thomasi, 



Buds small, narrow, twice as long as wide, %-ery sharp- 

 pointed, light liro\™; scales glabrous or merely 

 puberulent; leaves usually twice as long as wide, base 

 of petiole pubescent all around 4 U. alata. 



1. Lliiiiis fiilva Mifhaux. Slippery Elm. Red Elm. Plate 57 

 Fairly large trees with deejilj^ fissured reddish-brown bark without 

 white streaks between the layers of the ridges, twigs very pubescent 

 and green at first, becomnig graj' or reddish-ljrown at the end of the 

 season and remaining more or less pubescent for a year or more; buds 

 ovate, a very dark reddish l>rown, the scales more or less pubescent; 

 leaves ovate, oval or slightly obovate, average blades 8-15 cm. long, 

 hairy on both surfaces at first, remaining more or less pubescent beneath 

 until maturitj', and becoming very rough above with a few scattered 

 hairs remaining, fragrant when dried, fragrance remaining for j'ears; 

 fruit ripening the last of April or the first of May before or with the un- 

 folding of the leaves; samaia orbicular or obovate, usuallj^ longer than 

 wide, average size 13-17 mm. long and 9-12 mm. wide, the margin as 

 wide or wider than the seed, margin glabrous, seed densely pubescent 

 on both sides; wood hard, strong, light when well seasoned and. not 

 warping as badly as white elm. 



Distribution. — Quebec south to Florida, west to Texas, Nebraska 

 and North Dakota. Found in all parts of Indiana. In the prairies or in 

 the "flats" it may be absent in one or more contiguous counties and 

 may be entirelj" absent on the crests and uppei' slopes of ridges. It 

 prefers a moist well drained soil, and where it is found it is usuallj' 

 a frequent to a common tree, although rarely is it found as a very 

 common tree. It is usually associated with sugar maple, beech, white 

 ash, linn, tulip, white oak, etc. 



Remarks. — This tree usually is from 3-0 dm. in diameter and tall 

 for its diameter. However, larger trees occur. In the Ind. Geol. 

 Rept. 6:70:1875 mention is made of a tree in .lackson County that was 

 "18 feet in circumference." The uses of the wood are similar to that 

 of \vhite elm. The inner bark collected in spring is much used m 

 medicine under the name of slippery elm. 



