INTRODUCTION TO BOTANY. 103 
§ Valvular, valvaris, valvata. When the petals, or other 
parts, only touch each other at their edges. Composite, 
Araliacez. 
Induplicativa. When the petals, or other parts, only 
touch other, and are then folded inwards. Clematides 
viticelle. 
Twisted, obvoluta, contorta. When the petals, &c. are 
placed obliquely, and cover one another spirally. Dian- 
thus, Apocynie. a 
_ Alternate, alternata, alternativa. When the petals, &c. 
are placed in two or more rows, so that each petal of the 
exterior rows coyer two halves of the petals of the interior 
rows opposite to them. Liiliacez. 
Quincuncial, guincuncialis. When there are five pieces,’ 
two interior, two exterior, and a fifth, one side of which 
covers the interior pieces, and the other side is covered by 
the exterior. Calyces of rosee and dianthi. 
Covering, vexillaris. When one of the pieces, folded 
inwardly on the middle rib, encloses all the others which 
are placed*opposite to each other. Leguminosz. 
- Snail-like, cochlearis. When one of the pieces, being 
larger than the rest, and bent in a curve, covers all the rest. 
Aconitum, many labiate. 
Tiled, imbricata, imbricativa. When the pieces are in 
diverse series, and the exterior series being smaller than 
the interior, cover them only at the base. Involucra of 
many of the compositz, petals of double peionies. 
Calycular, calycularis. The pieces being in two series, 
the external covers only the base of the internal. In- 
volucra of the seneciones. 
Enveloping, convolutiva. When each exterior piece in 
succession is bent so as to cover all the pieces within it. 
Petals of cheiranthus, and of many other crucifere. 
Rumpled, plicativa. The pieces are folded, or rumpled 
up without any apparent order. Corolle of the papavera- 
ceze, Cistus, Punica. 
These are the principal variations that have been hitherto 
noticed, but the study of the flower-bud is still in its in- 
fancy, although of great use in ascertaining the natural 
affinity of plants. 
