44 ELEMENTARY BOTANY 
The terms posterior and anterior are used by botanists to 
denote the exact position of the floral leaves with regard to 
the stem; the side of the flower nearest the stem is the 
posterior side, that furthest away the anterior. In the dead- 
nettle, the two large petals forming the upper lip are on the 
posterior side of the flower ; the spur of the violet is on the 
anterior side, for it is furthest away from the main stem ; 
the large overlapping petal of the sweet pea is posterior. 
DESCRIPTION OF FLOWER OF VIOLET. 




















NumBeR, Union | PosiTIon 
an nes aE OF OF ON REMARKS. | 
' Leaves. Leaves.| RECEPTACLE. 
Calyx 5) Free Inferior The sepals project 
(sepals) : beyond the point 
of attachment ; 
the two anterior 
| sepals allow the 
spur to protrude 
Corolla — 5 Free Hypogynous The anterior petal 
(petals) | forms a spur 
Andrecium = 9) Free Hypogynous/The two anterior 
(stamens) oe stamens have 
appendages or 
| nectaries, which 
| | fit into the spur 
Grynecium 3 |Joined Superior — Placentation parie- 
(carpels) | tal, stigma hooked 



ee - * ee 
The floral diagrams representing the median, vertical section 
of a flower show whether it is hypogynous, perigynous, or 
epigynous. (See Fig. 34.) | : 
Floral Instead of writing out a technical description 
Formulas. of a flower, the union or non-union of parts, and _ 
the position of the floral leaves on the receptacle may be — 
expressed by means of formulas as follows: 
