xxvm 
INTRODUCTION. 
in successive sets, one within and above the other, as in a Buttercup (p. 8), 
Poppy (p. 26), &c., these organs are said to be hypogynous. When, on the 
other hand, the petals and stamens are inserted into the calyx , that is, cohere 
below with it (usually through the intervention of a ring or Disk which 
lines its base), as in the Cherry, Strawberry, &c.. they are perigynota. 
The same term is employed when all these parts likewise cohere with the 
base of the ovary, as in many Saxifrages, Heuchera (p. 149), &c. When 
all these parts adhere to or are incorporated with the surface of the ovary 
quite to its summit, as in Umbelliferae (p. 163), Dogwood (p. 167), also in 
the Fuchsia, and all the Evening Primrose Family (p. 134), so that these 
organs seem to spring from the top of the pod or fruit instead of beneath it, 
they are termed epigynous. 
155. Rarely the stamens further cohere with the style itself, when the 
flower is gynandrous , as in the Orchis Family (p. 463). 
* * Its Symmetry. 
156. A flower is perfectly symmetrical when the several whorls, or sets 
of organs, which compose it are equal in number, or are multiples of the 
fundamental number. The flower of Tillsea (p. 146) is entirely and ob¬ 
viously symmetrical, the sepals, petals, stamens, and pistils being un "°r*?\y 
3, or in some specimens 4. So is that of Sedum (Stone-Crop, &c., p. 14b)» 
where the parts are in fives, but the stamens are doubled, or, in other 
words, there are 2 whorls of them, which may be distinguished by some 
inequality in the length or time of the maturity of the two sets. Pentho- 
rum, the next genus (p. 147), is like the last, only the petals are usually 
wanting ( suppressed ), and the 5 pistils are partially united into one. The 
Lily (p. 494) is also symmetrically constructed on the ternary plan, viz. 
with all its parts in threes ; the 6-leaved perianth (132) consisting of 3 
outer ( sepals) and 3 inner parts ( petals ); the stamens 6, or two sets ; while 
the apparently single pistil consists of three wholly coherent into one. C& 
the other hand, the flower of Crucifers (p. 30) is unsymmetrical as to the 
stamens, which are 6, while the sepals and petals are only 4. 
157. The number of the component parts of the whole flower, or of any 
set, is designated by the terms binary (in twos), ternary (in threes, as in 
most Endogens), quaternary (in fours), quinary (in fives, the prevalent 
mode in Exogens), &c.; or sometimes by Greek numerals prefixed to 
-merous, as dimerous, of 2 parts ; trimerous, of 3 ; tetramerous, of 4 ; penta- 
merous , of 5; hexamerous, of 6, and so on. These and the like terms are 
frequently written with Arabic numerals, as 3 -merous, 4 -merous, &c. 
158. In the typical or normal symmetrical flower, the organs of each set 
successively alternate (85) with each other; that is, the petals stand 
over the intervals between adjacent sepals ; the stamens, or the outer 
whorl of them, over the intervals between the petals (or the lobes ot 
the corolla if monopetalous), and consequently opposite, or before, the 
sepals ; and so on. This regular alternation of parts is to be taken for 
granted in botanical descriptions, unless otherwise expressed. The excep¬ 
tions to this rule, when they occur, almost universally run uniformly through 
the family, as in Berberidaceae (p. 20), Rhamnaceie (p. 84), where the 
stamens stand opposite the petals ; and in Primulaceae (p. 280), where they 
are opposite the lobes of the corolla, which amounts to the same thing. 
159. That sepal, petal, or other part which, in an axillary flower (10), 
lies next the bract, or outwards as to the axis of the stem or branch, i 
termed the anterior or inferior (lower) ; those which are on the opposi e 
side, viz. next the main axis, are posterior or superior (upper) ; those whicn 
* For particular explanations and more extended illustrations of . the P lan !^ r Jj^ 
ture, symmetry, and modifications of the flower, .the student is referred to tne w 
tanical Text-Book, 2d ed., pp. 184-218. 
