POLYPETALAC^— ROSACEA 139 



drag the carina with them, because they are inter-locked with 

 {e.g. Pea), or actually joined to {e.g. Clover), the sides of 

 the carina. [Try and see what causes the wings and keel to 

 return to their places when the pressure of the bee is removed.] 



OTHER TYPES OF PAPILIONACE..E. 

 In the flower of the Broom and some other Papilionaceae the 

 filaments of all ten stamens are joined together, but there still 

 remains a small window-like opening on each side of the base 

 of the posterior stamen. These two openings render the 

 honey accessible to bees. The White Clover has a creeping 

 stem ; the Broad Bean ( Vtcia faba) is an erect plant ; the Pea, 

 Vetches, and others climb by tendrils, which are modified 

 leaflets ; whilst the Scarlet Runner {Phaseolus) has a twining 

 (left-handed) stem by which it climbs erect slender supports. 

 The Papilionacese have on their roots peculiar swellings or 

 tubercles, which are caused by microscopic fungi. The com- 

 pound leaves of many types display day- and night- movements. 



ROSACEAE (Rose Family) 



Herbs or shrubs. Leaves usually alternate, stipulate. 

 Flowers regular, usually perigynous. Sepals usually 4 or 5. 

 Petals usually 4 or 5, polypetalous. Stamens usually numerous, 

 bent inwards in the bud. Carpels, from i to 00 , usually apocar- 

 pous, usually superior ; styles more or less separate ; often 

 I or 2 ovules in each carpel. Fruit various. Seeds with 

 very little or no endosperm. 



Type I. : DOG ROSE {Rosa caninay 



Vegetative characters. — Shrub, with numerous prickles, 

 which are "subsidiary outgrowths." Leaves alternate, with 

 persistent stipules, pinnately compound with a terminal 

 leaflet ; margins of the leaf saw-like (serrate). Inflorescence 

 terminal; the flower terminates a branch ; in addition, one or 

 two subjacent bracts may have a flower in the axil of each. 

 [Look for the transitions between the foliage-leaves and bracts.] 

 Flower (fig. 168) actinomorphic, <? , cyclic; coloured and 

 scented. Sepals (cal) five. The sepals are imbricate in the 

 bud. The two external sepals have " beards " on both lateral 

 ■" Any Rose, save a double variety, may be selected for examination. 



