GROUP V. ANGIOSPERM^E ; DICOTYLEDONES. 557 



section, are pointed towards the exterior : the sub-genus Sorbus resembles 

 the preceding, but has pinnatifid leaves ; it includes P. Aucuparia, the 

 Mountain Ash or Rowan-tree, also P. domestica, the true Service-tree, and 

 P. torminalis, the Wild'Service-tree : the sub-genus Aria, includes P. Aria, 

 the White Beam. The genus Amelanchier includes the European A. 

 vulgaris, and A, canadensis, the June-Berry. The genera Raphiolepis 

 and Photinia (incl. Eriobotrya, the Loquat), include well-known culti- 

 vated flowering shrubs. 



Order 2. LEGDMINOS^E. Flowers usually dorsiventral, perigy- 

 nous, pentamerous, with calyx and corolla : stamens ten or more : 

 ovary of a single anterior carpel ; ovules borne on the ventral 

 suture : fruit a legume or a loinentum : flowers always lateral : 

 leaves nearly always compound. 



The Leguminosae, more particularly the Papilionese, are remarkable 

 physiologically by the presence of tubercles on their roots, caused by the 

 attack of a Fungus, and by their extraordinary faculty of nourishing in 

 soils poor in combined nitrogen (see p. 191). 



Sub-order 1. PAPILIONE^E. Flowers 

 dorsiventral, papilionaceous (Fig. 272 A). 

 The five sepals, the odd one being an- 

 terior, are usually connate, forming a 

 tube above the insertion of the corolla 

 and the androecium : the five lobes are 

 usually unequal and sometimes form 

 two lips, the lower of three and the 

 upper of two teeth : petals five, alternate 



with the sepals, imbricate so that the 



, , , FIG. 369. Flower of Lotus covjucu- 



anterior petals are overlapped by those , atug (gomewhat ma ^ A With one 



behind them ; the posterior petal is a ia removed ; k calyx ; fa vexillum ; 

 much enlarged, and is called the vex- fl ala; s carina. B With the corolla 

 ilium (Fig. 369.4, /a); the two lateral removed; rtube formed by the nine 



petals, which are much smaller, are *" 8tamen; ' 



termed the alai (Fig. 369 A, fl) ; the two 



anterior petals are connate or sometimes simply apposed, and form a hollow 

 boat-shaped body, the keel, or carina (Fig. 369 A, *). In a few cases the 

 corolla is entirely or partially suppressed ; thus in Amorpha, only the 

 vexillum is present. The ten stamens belong to a single whorl, with 

 direct diplostemony ; they are either connate and monadelphous, forming 

 a tube, or the posterior stamen may be free, so that the tube consists of 

 nine stamens, and is incomplete posteriorly (Fig. 3695), in which case the 

 androecium is diadelphous (9-1) ; rarely the stamens are all free ; they 

 mostly curve upwards, and diminish in length from in front backwards. 

 The ovary, enclosed by the staminal tube, consists of a solitary anterior 

 carpel ; it is often divided into chambers by a spurious longitudinal 

 septum, or by transverse septa into several chambers. The fruit is 

 usually a legume or a lomentum (Fig. 288 A), rarely one-seeded, and 



