THE STEM 29 



are sinistrorse, or coil towards the left or counter- 

 clock-wise, as kalai {Phaseolus), shim (Doltchos). The 

 latter are more common than the former. The direc- 

 tion of the spiral is generally constant in any given 

 kind of plant. For instance, all Ipomcea and all 

 Convolvulus are sinistrorse, whereas all Dioscorea are 

 dextrorse. A very few plants seem able to climb 

 equally well either way. Dense tropical forests of 

 lowland river-basins consist of giant trees to whose 

 tops gigantic woody climbers called lianas rise and 

 run along from one end of the forest to the other, 

 forming loops and wreaths. Common lianas of 

 Bengal are madhabi-lata {Hiptage Madablota) and 

 several species of kanchan {Bauhinia). 



Stems are usually more or less round in outline, 

 that is, their transverse sections are more or less cir- 

 cular. The following noticeable divergences from 

 this type are, however, common : for example, in 

 tulsi (Ocimuni), ghal-g'hase {Leucas aspera), and most 

 plants of the tulsi family, the stems are square, while 

 in madurkati {Cyperus tegetum), mootha {Cyperus 

 rotundus), and other Sedges, they are triangular. 



Plants that live for a year, or rather a season, are 

 known as annuals, or season plants, as are most of 

 our field-crops, like Rice, Mustard, Jute, Radish, &c. 

 Those that live for two years are known as biennials. 

 Plants that live for a number of years are known as 



PERENNIALS. 



Plants are usually classified into herbs, shrubs, or 

 trees. The annuals, the biennials, and most of the 

 plants with underground perennial stems are herbs. 

 Most of the herbs have soft tissues; in fact, the term 

 HERBACEOUS is uscd with respect to any plant or part 

 of a plant which consists of soft tissues, whereas the 

 term woody is used with respect to any plant or part 



