Aruncus 



Rosaceae 



527 



50 



Map 1089 



Spiraea tomentosa L. 



it becomes infrequent to very rare or possibly absent in a few counties 

 of the unglaciated region. 



Ont. to Sask., southw. to N. C. and Miss. 



2. Spiraea tomentosa L. (Spiraea tomentosa var. rosea (Raf.) Fern.) 

 HARDHACK. Map 1089. Hardhack requires a slightly acid soil and is fre- 

 quent to common in the lake area as shown on the map. I have seen areas 

 from an acre to not less than ten acres in extent in low flats where this 

 species was the principal ground cover. South of this area it is absent 

 until the pin oak and sweet gum flats of the southern counties are reached 

 where it is sometimes found but generally in very limited numbers. 



When a large colony is studied one finds that most of the specimens have 

 elongated and narrow inflorescences but on more vigorous specimens the 

 inflorescences are often spreading. The tomentum on the capsules varies 

 in abundance but the capsules never become entirely glabrous. 



N. S. to Man., southw. to Ga. and Kans. 



3322. ARUNCUS [L.] Adans. 



1. Aruncus dioicus (Walt.) Fern. (Rhodora 41 : 423. 1939.) (Aruncus 

 Sylvester Kost. of Indiana authors and Aruncus Aruncus (L.) Karst.) 

 Common Goatsbeard. Map 1090. This plant is restricted almost entirely 

 to the unglaciated part of the state. It is local to very local and grows on 

 the bluffs of streams and on steep, wooded slopes. It is often found clinging 

 to the brink of the top of steep, washed slopes and often is associated with 

 Hydrangea. 



Ind. to Iowa, southw. to Ark. and Okla. 



3325. GILLfiNIA Moench 



Leaflets beneath covered more or less with sessile or stalked glands; stipules mostly 

 foliaceous, more or less incised 1. G. stipulata. 



Leaflets glandless beneath; stipules small, usually less than 5 mm wide, entire to ser- 

 rate. (See excluded species no. 300, p. 1058.) G. trifoliata. 



