84 : ELEMENTARY BOTANY 
Sweet Pea, Vetch ; Scarlet Runner by means of its stems; 
Lathyrus aphaca by its petioles (Plate I., Fig. 33). Some are 
-shrubs—Genista, Broom, Gorse, and these three are spinous ; 
others are trees, as Laburnum and many tropical genera. 
Spécial _ The papilionaceous corolla is an invariably 
Structures. constant. feature of this Order in Britain. In 
South Europe and in the tropics, many shrubs and trees . 
belonging to the Order have not a papilionaceous corolla. Of 
these the best known in England is the Mimosa, or Sensitive 
plant, characterised by its day and night movements (Figs. 
149, 150). 
- In some genera of this Order the ten stamens are all joined, © 
as in the Furze, Broom, Genista, Rest-harrow, Lady’s-fingers. 
In the Clover the corolla is attached to the staminal tube, not 
to the receptacle. 3 
The fruit is usually a legume, but in the Acacia and some 
other genera the pod dehisces transversely, each portion con- 
taining one seed. The black, spirally twisted fruit of the 
Medick may be noticed. 
Next to the Composite this is the most 
extensive Order of Flowering Plants, and is dis- 
tributed over the whole globe. 
Distribution. 
ROSACEAL. 
The genera included in this Order differ from each other 
more than is usually the case, owing to the varied forms of 
the receptacle. The flowers are, with the exception of the 
Apple group, perigynous ; the receptacle is often hollowed out, 
enclosing the carpels. 
The following plants, Blackthorn, Rose, Apple, may be 
taken as types of the three tribes into which many botanists 
group the different genera belonging to the Order. 
BLACKTHORN. 
To this division belong the Plum, Cherry, Almond. 
Blackthorn is a shrub, or tree, with branches converted into 
spines, or thorns (p. 25). The flowers come out before the 
leaves, are therefore very conspicuous, and attract insects. 
Type I. 
