174 CONTRIBUTIONS FROM THE NATIONAL, HERBARIUM. 



2. SPIEAEA L. 



Flowers about i cm. wide, on slender pedicels 1. S. prunifolia. 



Flowers KUiall, iu close clusters. 



Leaves thin, glabrous 2. S. latifolia. 



Leaves thick, woolly beneath 3. S. tomentosa. 



1. Spiraea prunifolia Sieb. & Zucc. 



Cultivated and sometimes escaped. Apr. Originally from Japan. 

 Flowers often double. 



2. Spiraea latifolia (Ait.) Borkh. Meadowsweet. 

 Rocky places; infrequent. July. Northern states, south to Va. 



3. Spiraea tomentosa L. Hardhack. 

 Low ground; rare; Sligo Creek (Oldys); southwest of RockviUe (HUchcoch). July. 



Northern states, south to Ga. 



3. ROSA L. Rose. 



Leaflets 3-5; styles coherent in a protruding column 1. R. setigera. 



Leaflets 5-many; style? distinct. 



Calyx lobes deeply incised, erect on the fruit, persistent 2. R. canina. 



Calyx lobes deciduous, spreading 



Leaflets finely and evenly serrate 3. R. palustris. 



Leaflets coarsely serrate. 



Infrastipular spines slender, nearly straight 4. R. virginiana. 



Infrastipular spines stout, with a broad base, curved .5. R. rubiginosa. 



1. Rosa setigera Michx. Climbing rose. 

 Thickets; infrequent. June. Eastern TJ. S. 



2. Rosa canina L. Dog rose. 

 Thickets and roadsides; rare. May. Cultivated in gardens; originally from Eur.* 



escajied in the eastern U. S. 



3. Rosa palustris Marsh. Swamp rose. 

 Borders of swamps and streams; frequent. June. Eastern U. S. {R. Carolina of 



authors, not L.) , 



4. Rosa virginiana Mill. 



Borders of swamps; frequent. June. Northern states, south to Md. [R. lucida 

 Ehrh.) 



5. Rosa rubiginosa L. Sweetbrier. 

 Rocky i") laces and open ground; frequent. June. Introduced from Eur. 



4. RUBUS L. 



Leaves simple, 3-5-lobed; flowers 3-6 cm. wide, purple-red 1. R. odoratus. 



Leaves compound; flowers white. 

 Fruit falling away whole from the dry receptacle; petals shorter than the calyx; 



plant conspicuously glaucous 2. R. occidentalis. 



Fruit not separating from the juicy receptacle; petals longer than the calyx; plants 

 not conspicuously glaucous. 

 Stems erect or ascending, not prostrate or trailing. 

 Leaves wedge-shaped at base, pale-velvety beneath; pedicels armed vvith 



prickles 3. R. cuneifolius. 



Leaves not conspicuously wedge-shaped nor pale- velvety beneath; pedicels 



unarmed 4. R. argutus. 



Stems prostrate or trailing. 

 Stems armed with numerous weak prickles, these not confined to the angles. 



5. R. hispidus. 

 Stems armed with stout prickles on the angles 6. R. prooumbens. 



