22 



DOMESTIC BOTANY. 



grow and maintain themselves entirely on trees without 

 any connexion with the ground, such being called epi- 

 phytal, of which the numerous tropical orchids and 

 tillandsias are familiar examples. 



Although all climbing and twining plants are consi- 

 dered to have slender flexible stems, many of them in 

 age attain a foot or more in diameter, becoming firm like 

 tree stems. Some assume curious forms ; in a species of 

 Himalayan vine the stem is flat and thin, hanging from 

 trees like machinery bands, and in a Brazilian Bauhinia 

 they are broad and bent in a zigzag manner, conveying 

 the idea of stair steps. 



There is a set of low plants that grow in tufts, remain- 

 ing green all the year, of which the pink, carnation, sea- 

 thrift, saxifrage, sedum, blue and yellow alyssum, and 

 dwarf fig marigold are examples. In gardens they are 

 always ranked with herbaceous plants, but their perma- 

 nent stems give them more the character of shrubs. I 

 therefore apply to them the term frutlets. The evergreen 

 candytuft may be considered to hold an intermediate 

 position between them and hard-wooded shrubs. 



Sarcocauls (fleshy stemmed plants). — This term is ap- 

 plied to stems composed of soft succulent matter, gene- 

 rally surrounding a woody centre; the cactus family, 

 African euphorbs and Stapelias afford familiar examples. 

 Plants with this kind of stem are leafless, and often 

 three- four- five- or many-sided, or furrowed ; they 

 are also globose, pyramidal, or conical, and are either 

 smooth, as in the melon-shaped euphorb, or prickly, as 

 in the Echinus section of cactse. Flagelliform, or cord- 

 like stems, are represented by the creeping cereus and its 

 allies ; some are also perfectly flat and more or less broad. 



Stems are called articulated when composed of pieces 



