100 THE BUCKTHORN FAMILY. [Rhamnui. 



The Sumachs of our shrubberies (species of Rhus) belong to the large 

 family^ of Tercbvnthacece, widely spread over the temperate and hotter 

 regions of the globe, but unrepresented in Britain. They are usually 

 shrubs or trees, with mostly compound leaves, snjall regular flowers 

 definite stamens, inserted under a perigynous disk, quite free from the 

 ovary, and no albumen in the seed. 



XXV. PAPILIONACE-E. THE PEAFLOWER TRIBE. 



(A Tribe of thelLeguminous family, or Leguminosce.) 

 Herbs, shrubs, or trees; the leaves alternate (or, in a few 

 exotic genera, opposite), usually furnished with stipules, simple 

 or more frequently compound ; the leaflets either pinnately or 

 digitately arranged on their 'common stalk. Flowers in axillary 

 or terminal racemes or spikes, rarely solitary. Sepals combined 

 into a single calyx, more or less divided into 5 or fewer teeth 

 or lobes. Corolla very irregular, consisting of 5 petals; the 

 upper one, called the standard, is outside of all in the bud, and 

 usually the broadest; the two lateral ones, called wngs, are 

 between the standard and the two lower- ones, which are inside 

 of all, and united more or less by their outer edge into a single 

 one called the keel; the claws of all 5 petals remaining free. 

 Stamens 10, the filaments in the British species either mona- 

 delphous, all united in a sheath round the ovary, or diadelphous, 

 when the upper one is free and the other nine united in a 

 sheath. Ovary single, 1-celled, with 1, 2, or more ovules arranged 

 along the inner or upper angle (the one next the standard) of 

 the cavity. Style simple. Fruit a pod, usually opening in 2 

 valves. Seeds with 2 large cotyledons and no albumen. 



A very numerous tribe, widely distributed over the whole surface of 

 the globe, and easily known by the peculiar form and arrangement of 

 the petals, constituting the well-known peaflower called by botanists 

 papilionaceous, comparing it, by a not very intelligible stretch of imagi- 

 nation, to a butterfly. The whole family comprises two other tribes or 

 sub-orders, chiefly tropical or southern : the Casalpinia tribe, repre- 

 sented in our plantations by the Judas-tree (Cercis) and the Gleditschia, 

 or, in our plant-houses, by Cassias, Bauhinias, and others ; and the 

 Mimosa tribe, to which belong the Sensitive-plant (Mimosa pudica), the 

 Calliandras, and the numerous Australian Acacias. The LeguminoscR 

 thus form, after the Composites, the most extensive of all the Natural 

 Orders of flowering plants. 



.( Leaves simple, or with 3 leaflets .... 2 



I Leaves pinnate, with 2, 4. or more leaflets .... ... 12 



(Calyx distinctly divided into 2 lips, either entire, or the upper ^one 2-toothed 



2-i and the lower one 8-toothed . 8 



(Calyx with 5 distinct teeth, not arranged in 2 lips 5 



./Calyx yellow, nearly as long as the petals, deeply divided into two 1 ULEX. 



1 1 Calyx short, not divided below the middle ...... 4 



