FAMILIES OF FLOWERING PLANTS 



127 



yellow, rarely purple or white flowers, and either palmate or pinnate 

 compound leaves, those of the palmate type being frequently composed 

 of five leaflets, so that the plants have received the name of cinquefoil 

 or five-finger. The closely allied genus Comaram illustrates practically 

 the same type (see Fig. 112). The tormentil {P. Tormeiitilla) is the 

 only species possessing marked medicinal properties. Fragaria, the 

 strawberry, is another genus whose members are mainly of northern 

 distribution. Wild strawberries, of one sort or another, occur through- 

 out the country; and we are all familiar with the advances made by 

 horticultural science in the domes- 

 tic strawberry. It should be pointed 

 out that the edible portion of this 

 fruit consists of the enlarged pulpy 

 axis or receptacle, while the so-called 

 " seeds " embedded on its surface are 

 the real fraits, each being a small 

 one-seeded achene. In the raspberry 

 and blackberry, members of the 

 genus Bitbus, the fruit is of wholly 

 different structure, consisting of a 

 coherent mass of little stone-fruits 

 or drupes, which when ripe pull easily 

 away from the dry columnar recep- 

 tacle. Ruhus is likewise of temper- 

 ate distribution, but its species are 

 found in several continents; they are 

 especially numerous and very diffi- 

 cult to identify in Europe. The lit- 

 tle Arctic and alpine herbs belong- 

 ing to the genus Dryas are somewhat 

 similar to the preceding in the appearance of their flowers, but the nu- 

 merous achenes, when ripe, are tipped with long plumose styles like 

 those of a clematis. In Gemn, a genus which furnishes some ornamen- 

 tal species, the styles are also persistent, but not always plumose. The 

 same floral stmcture may be seen in the mountain mahogany {Cercocar- 

 pus) and several allied trees of the western States. The herb known as 

 agrimony {Agrimonia Eupatoria) was formerly of much repute in med- 

 icine. Its leaves and rootstocks are astringent, the latter yielding a 

 yellow dye. Several species of this genus occur in the United States; 

 the calyx of the small yellowish flowers is beset with bristly hooks, 

 which furnish a means of artiflcial transportation for the ripe fniit along 

 with other "stick-tights." The burnets belong to the genus Sangui- 

 sorha; they are tall herbs with spikes of small white flowers. In this 



Fig. 112. The marsli cinquefoil or cow- 

 berry (Comaruin palustre). After Britten & 

 Brown, 111. Fl. Northeast. U. S. 



