If you really want to understand botany, you have to understand a few of the more complex terms that are not necessary to know when using the field guides by Peterson or Newcomb. But, using these guides you are not led to an understanding of how and why plants are grouped as they are. So if you really want to understand botany, learn the following terms.
Hierarchial Divisions for Various Species
|kingdom||Prokaryotae (archaebacteria, cyanobacteria), Protoctista (algae), Fungi, Plant, and Animal|
|division||Coniferophyta or Angiospermophyta|
|class||Dicots or Monocots|
|subclass||6 Dicot Subclasses and 4 Monocot Subclasses|
|order||groups of families|
|family||groups of genera|
|genus||groups of species|
|species||species the individual, distinct plant|
I. Gymnosperms and Angiosperms
|leaves needle or scale-like||leaves net-veined|
|Fruit with no fleshy covering||Gymnosperms (naked seed) (pines, cypress, etc.)||-----|
|Fruit with fleshy covering||-----||Angiosperms (flesh-covered seeds) (non-neetled leaved plants)|
II. parts of the flowers:
flower -- the reproductive structures of the plant
petals -- the usually fleshy part of the flower structure;
corolla -- all the petals considered as a whole;
sepals -- the outer elements surrounding the ovary, which in many species, such as the rose, hold the petals together;
calyx -- all the sepals considered as a whole;
perianth -- all the petals and sepals considered as a whole;
stamens -- the male structures that contain the pollen (that in turn delivers the sperm);
pistils -- the female structures that contain the ovaries that receive the sperm from the pollen grains.
Parts of the stamens:
anther -- the top of the filament of the stamen that contains the pollen;
filament -- the stalk which holds the anther(s) up so the pollen can be carried away by the wind or by insect pollinators.
Note on stamens (Gleason and Cronquist, 1991):
centripetal = spirally arranged stamens (not in definite cycles);
centrifugal = organization of stamens into cycles and/or fascicles;
With evolution the number of stamens proceeds from many to few. In primitive plants there are numerous stamens in an indefinite spiral.
The next progression is for the stamens to be organized into several cycles. These several cycles are offset from each other in the same way that the cycle of petals is offset from the cycle of sepals. The outermost set of stamens is normally alternate with the petals (and opposite the sepals), the next set is opposite the petals, and so on.
With evolution, whole cycles of stamens may be dropped out at once. Thus the progression might go from numerous and spiraled, to four cycles, to three cycles, to two cycles (Caryophyllaceae, Geraniaceae), to a single cycle. Other evolutionary possibilities are a a melding of two cycles (Acer of Aceraceae, Sapindaceae) and only the second cycle is retained (stamens opposite the petals; Primulaceae).
Parts of the pistil:
ovary -- the usually round structure that contains the seeds of future plant generations. After pollination, the ovary develops into the fruit;
style -- the tube connecting the ovary and the stigma, down which the sperm travels to get to the seeds within the ovary;
stigma -- the top (usually a knob) of the style on which the pollen lands via the wind or insect or other animal pollinators.
Types of flowers:
(See the section on helpful shortcuts to flower identification). Some specialized flower types that are very useful to know are:
catkins -- flowers without petals that look like caterpillars and are often found in genera of the witch-hazel subclass;
spathe and spadix -- the spathe is a hood over and covering the spadix, which contains the flowers and is usually round or spike-like.
inflorescence = all the flowers considered together, whether it is one or one hundred individual flowers
Two types of inflorescences (from simplest to most complicated):
1. Racemose (indeterminate = the lowest or outermost flowers bloom first, further flowering taking place toward the top or center)
remember the term SYRUP (dropping the vowels leaves SRP) for spike, raceme, and panicle.
raceme -- flower attached to the stem via a single flower stalk. Seen in Campanula (bellflower) and Saxifraga (saxifrage).
It is not primitive. Common in more advanced families such as mustard (Brassucaceae), pea (Fabaceae), and snapdragon (snapdragon) families.
spike -- flowers attached directly to the stem without a flower stalk (sessile). It is a raceme with the pedicels suppressed.
panicle -- the flower stalk divides into two or more parts, us. each with a flower. A panicle is a branched raceme.
head -- a raceme with both the internodes and the pedicels very short or suppressed.
corymb -- a raceme with elongate lower pedicels and relativel short axis.
umbel -- a raceme originating from one point with the flowers in a rounded structure.
compound umbel -- an umbel with an additional umbel at the end of each primary pedicel. An umbel is in Liliaceae (lily family) and more specifically in the Allium genus (field garlic, wild onion).
2. Cymose (determinate)
Each of the forms of racemose inflorescene has its cymose counterpart. Here the outermost (lowermost) row of flowers blooms immediately after the terminal flower.
A cyme is a type of inflorescence that has the terminal flower blooming first and usually with with the terminal flower of each branch blooming before the others on that branch. The diminutive of cyme is cymule, and this refers to the ultimate brachings of compound cymes. A dichasium is a three-flowered cymule in which the development of the terminal flower is followed by that of the two opposite lateral flowers. A dichasial cyme is repeatedly branched in dichasial fashion. Further divisions of the dichasial cyme leads to a compound dichasial cyme. Compound dichasial cymes are seen in families such as pink (Caryophyllaceae) and madder (Rubiaceae). This type of inflorescene is seen especially in plants that have opposite leaves.
Heluciud cymes are frequent in Boraginaceae and Hydrophyllaceae.
In a scorpioid cyme the branches are alternately on opposite sides of the developing sympodial axis, so that the axis has a zig-zag appearance.
|A. originates at various point along the infl. stalk|
|B. originate from one point|
|twice pediceled||compound umbel|
|A. raceme with long primary pedicel||cyme||heloid cyme & scorpioid cyme|
|B. twice pediceled||compound cyme|
IV. floral formula -- the number of petals, sepals, stamens and styles.
5 5 5 5 = five petals, five sepals, five stamens, and five styles
N = numerous
( ) = fused; for example, (5) = five fused petals
1+2+2 = five petals, in this case for the pea family pattern of 1 standard, 2 keels, and 2 wings.
(2/3) = five petals in a two over three irregular pattern, as in Lobelia
z = irregularly placed petals.
types of leaves:
entire -- leaves not toothed;
toothed - leaves with small or large indentations on the margins;
lobed -- deep or somewhat deep indentations (called sinuses) in the margins of the leaves.
types of leaf structures:
alternate -- each individual leaf has its own leaf bud; the leaves are located on either side of the branches; also, the branches are located on either side of the main branches;
opposite -- each individual leaf has its own leaf bud; the leaves and branches are opposite each other;
divided or compound -- each individual leaflet does not have its own bud; only the leaf (connected to the branch) has its own bud.
TYPES OF OVARY PLACEMENT
|no hypanthium||with hypanthium only||hypanthium joined to the ovary|
|position of the ovary vis-a-vis the point of attachement of the stamens, petals, and sepals|
|ovary sits on top||superior||hypogynous||perigynous|
|ovary half-way||half-inferior||partly epigynous|
|ovary sits below||inferior||epigynous|
The subclass with a large number of families with superior ovaries is witch-hazel. The rose sublcass is of mixed types, while the other subclasses of dicots are heavily hypogynous.
A = alternate-leaved
B = basal-leaved
D = divided
E = entire
L = lobed
O = opposite-leaved
T = toothed
W = whorled
cal = calyx
cor = corolla
pet = petals
sep = sepals
infl = inflorescence
flwr = flower
example of compound usage of the abbreviations:
AT = alternate-toothed leaves