344 



GLOSSAET. 



rachis : the main axis (midrib) 

 of a compound leaf or of an 

 inflorescence. Also applied to 

 the shaft of a feather. 



radicle : the root of the embryo 

 plant which emerges from the 

 seed on germination. 



receptacle : the top of the flower- 

 stalk from which the parts of 

 the flower arise. 



rhizoid : the structures which 

 perform the work of roots in 

 mosses and in the prothallus 

 of ferns. They are not true 

 roots. 



rhizome : an underground stem 

 or rootstock giving rise above 

 to buds and leaves, and to 

 adventitious roots below. 



runner : a creeping shoot grow- 

 ing along the surface and 

 rooting and giving rise to 

 buds at the nodes. 



samara : a dry, non-splitting 

 winged fruit, e.g. as in Ash, 

 Elm, Birch, etc. 



sepals : the parts of the outer- 

 most whorl of the flower, i.e. 

 the calyx. 



serrate : toothed like a saw. 



sessile : without stalk. 



silicula : a short and broad 

 fruit of the siliqua type, e.g. 

 fruit of Shepherd's Purse. 



siliqua : a slender pod-like fruit, 

 whose two valves split off 

 leaving the seeds attached to 

 the margins of a middle mem- 

 branous partition, e.g. fruit of 

 Wallflower. 



sorus : a cluster of spore -con- 

 taining capsules (sporangia) 

 occurring on the fronds of 

 ferns. 



spine : a sharp woody structure ; 

 a modified branch, leaf, or leaf 

 stalk. 



spiracle : an opening leading 

 into the breathing system of 

 insects. 



sporangium : the spore -contain- 

 ing capsules on the fronds of 

 ferns. 



stamen : the essential male 

 structure in a flower. A sta- 

 men consists of a stalk (fila- 

 ment) which bears an anther 

 (pollen-producing part) at its 

 tip. The filament is continued 

 up the back of the anther as 

 the connective. 



ctigma : the part at the ter- 

 minal portion of the style 

 which is modified for the re- 

 ception of the pollen grains. 



stipules : leaf-like appendages 

 at the base of the leaf stalk, 

 characteristic of certain plants. 



stomata : openings upon the 

 epidermis of leaves and young 

 stems for gaseous interchange 

 and transpiration of moisture. 



style : the upper part of the 

 carpel or carpels, usually 

 elongated, which bears the 

 stigma. 



tarsus : the ankle region in 

 vertebrates. The terminal 

 joints in the legs of insects. 



testa : the coat of the seed. 



thorax : the chest region. In 

 insects the middle division of 

 the body consisting of three 

 fused segments. 



transpiration : the giving off by 

 leaves of water absorbed by 

 the roots. 



tuber : a portion of an under- 

 ground stem or adventitious 

 root thickened with food store. 



umbel : a flat- topped inflorescence 

 in which all the flower-stalks 

 arise at the same level, laterally 

 from a reduced main axis. 



