214 PRACTICAL COURSE IN BOTANY 
IV. SPECIALIZED FLOWERS 
MareriaL. — For spring and early summer: sweet pea, black locust, 
wistaria, lupine, or any of the characteristic butterfly-shaped flowers of 
the pea family. For autumn or late summer: tropzolum, monkshood, 
or a bilabiate flower — snapdragon, digitalis, dead nettle, salvia, catalpa, 
etc. — of the mint or figwort family. 
237. Irregularity and specialization. — Irregularity and 
bilateral regularity are, as a rule, indicative of specialization, 
or adaptation to a particular purpose, such as the ready 
distribution of pollen, or its protection against injury. These 
adaptations are more noticeable in the corolla than in other 
parts, and hence flowers of this kind are usually classed 
according to the shape of their corollas. The most highly 
specialized flowers in this respect are the orchids, but they 
are too rare and difficult of access to be available objects for 
study. The most familiar and widely distributed kinds of 
specialized corollas are the bilabiate, or two-lipped, and the 
papilionaceous, ov butterfly, forms. The first is characteris- 
tic of the mint and figwort families, of which the toadflax, 
sage, and catalpa are familiar examples. The second com- 
prises the well-known papilionaceous flowers of the pea 
family, named from the Latin word papilio, a butterfly, on 
account of their general resemblance to that insect. 
238. Dissection of a papilionaceous flower. — Sketch a 
blossom of any kind of pea or vetch as it appears on the 
outside. Are the sepals all of the same length and 
shape? If not, which are the shorter, the upper or the 
lower ones? P 
Turn the flower over and examine its inner face. Notice 
the large, round, and usually upright petal at the back, the 
two smaller ones on each side, and the boat-shaped body 
between them, formed of two small petals more or less united 
at the apex. Press the side petals gently down with the 
thumb and forefinger and notice how the essential organs are 
forced out from the little boat in which they are concealed. 
