184 GLOSSARY 



Stigma (Greek, stigma, a spot). The portion of the pistil which 

 receives the pollen. It is often hairy or sticky. 



Stipules (Latin, stipula, straw, stubble). The bodies borne where 

 a leaf joins on to a stem ; not present in all plants. 



Stoma (plural, stomata) (Greek, stoma, a mouth). The small 

 pores in the surfaces of leaves, and other green parts of plants. 



Sucker. This is used botanically in two senses, (i) For a branch 

 which starts underground, and then comes above. (2) For a 

 special sucking apparatus by means of which some young 

 plants empty their seeds of food. 



Tendril A thin structure, branched or not, by means of which a 

 plant climbs. Stems and leaves are frequently modified to 

 form tendrils. 



Transpiration (Latin, trans, across ; spiro, I breathe). The giving 

 off of water- vapour through the stomata of plants. 



Tuber (Latin, tuber, a swelling). A thickened, usually underground 

 structure, which may be a root or stem. Important as store- 

 houses of plant food. 



Variation (Latin, variatio, a difference). Used to express the 

 tendency of living things to differ to some extent from 

 the ordinary type. The differences which enable us to dis- 

 tinguish different persons from one another, afford an everyday 

 illustration of variation in human beings. 



Vitality (Latin, mtalis, of or belonging to life). Seeds, for instance, 

 are said to retain their vitality so long as they are capable of 

 growing when placed under suitable conditions. 



