No. 423} NORTHERN POLYPETALOUS FLOWERS. 219 
strawberry), which is certainly closely allied to the line of the 
field strawberry. | Wa/dsteinia fragarioides, or the barren straw- 
berry, which in leaf habit has the aspect of Fragaria, is likewise 
yellow. The simpler species of avens are yellow or white, while 
those with the honey concealed are purple. In Geum rivale 
(purple avens) the petals are purplish orange and the calyx 
brown purple. The honey can be reached only by long-tongued 
bees and flies, such as Bombus and Rhyngia. In Comarum 
palustre (marsh cinquefoil) the petals are purple and the sepals 
also inside. The plant grows in swamps and is visited by flies 
and less frequently by bees. The primitive color of both these 
species seems to have been yellow. The purple-flowering rasp- 
berry, Rubus odoratus, is however derived from white-flowered 
progenitors, for in New York at Pine Hill, Ulster County, a 
white-flowered form occurs, and the white species of this genus 
are frequently reddish or purple. 
The ten species of Rosa in the northern states are rose or 
pink, varying to white. Though the flowers contain no honey, 
their color and fragrance attract many insects to the ample store 
of pollen. Several species have odors so peculiar that they may 
be recognized by them alone. The theory of Delpino that the 
distribution of this genus was determined by the range of certain 
families of Coleoptera has been disproved by the observations 
of Müller and others who have found bees very frequently upon 
the flowers. Beetles may often be collected, some species of 
which devour the petals bodily. The flowers of Rosa canina 
. gain increased conspicuousness by always turning towards the 
sun. In Germany they are visited by eight beetles, six bees, 
and two flies. 
The family of the Rosacez is very prolific in hybrids, and 
more than two hundred have been observed in nature, Innu- 
merable hybrids of Rosa have been produced under cultivation 
which display countless combinations of yellow, red, and white, 
—as white tinged with yellow or pink, yellow fading to white 
or shaded with rose, or pink changing to white, rose shaded with 
yellow, or intense coloring such as crimson, carmine, and scarlet. 
In one variety on the same root there are produced every inter- 
mediate shade between white and red, and in another the colors 
