67 A400 Structural and Physjological Botany, = = 
variously united afterwards with the calyx-tube, or enclosed in the _ 
swollen top of the peduncle ; styles usually distinct or only one. | 
Order 1. LEGUMINOS&. Herbs, shrubs, or trees, with stipulate > 
leaves, usually alternate and compound. Calyx either imbricate or val- — 
vate in bud, 2-lipped, 5-cleft or 5-toothed, the odd section being 
below ; very rarely 4-cleft; petals equal in number to the calyx- 
teeth, seldom fewer ; stamens usually double as many, often much 
more numerous. The monocarpellary, unilocular, free, superior ovary 
‘develops into a legume or lomentum, bearing on its ventral suture the 
seeds, which have no or very little endosperm. 
This very large and important order is divided into three well-marked 
ea as follows :— 
. Papilionacee. (Figs. 514-516.) Herbs, shrubs, or trees of very 
Ok habit, usually with alternate and compound, pinnate or digitate 
leaves. The petiole has two stipules, and sometimes each pinna has also a - 
stipella ; the stipules are sometimes transformed into thorns [or tendrils]; 
and the petiole frequently ends in a tendril. The flowers are seldom 
solitary, usually collected into spikes, racemes, or umbels, but never in 
compound inflorescences. The calyx is gamosepalous, 5-toothed, and often 
2-lipped ; the corolla attached to its base, and irregular, 5-leaved, and 
papilionaceous. The two inferior petals are mostly more or less coherent 
and form the eel or carina (see Fig. 253, p. 152), the two lateral ones 
being the wes or ale, and the superior the standard or vexillum. Some- 
times all the petals are coherent into a tube [as in Z7ifolium]. The fila- 
ments of the ten stamens are either coherent into a tube (#onadelphous) 
surrounding the pistil, or nine of them form a tube open above, the tenth 
lying in front of the cleft (diadel/phous). ‘The ovary is superior, bearing the 
ovules on its ventral suture ; usually unilocular, but sometimes, as in 
Astragalus (Fig. 288, p. 142), almost bilocular from the folding in of the 
margin of the carpel. The fruit isa unilocular capsule (/egume), splitting 
into two valves by both dorsal and ventral suture; but sometimes nearly 
bilocular, like the ovary, or multilocular by the formation of masses of 
cellular tissue between the seeds ; and then it sometimes breaks up into 
sections by the contraction of the pericarp between the seeds, when it 
is termed a lomentum (Fig. 516, 11.); rarely indehiscent, as in the sainfoin. 
The seeds are usually exalbuminous, rarely with a small endosperm ; 
the embryo curved, with the radicle lying on the cleft of the cotyledons. 
[Among the more important genera are Baptista, Crotalaria, Lupinus, — 
Genista, Ulex, Cytisus, Ononis, Trigonella, Medicago, Melilotus, Trifolium, 
Anthyllis, Lotus, Psoralea, Indigofera, Wistaria, Robinia, Colutea, ah : 
_ Astragalus, Oxytropus, Glycyrrhiza, Ornithopus, Coronilla, Hippocrepis. Bort 
Pie deumn, Onobrychis, Adesmia, Arachis, Desmodium, Cicer, Vicia ee Peay 
