_Flowers and Fruit._
The author hopes that those who use this work in studying trees will
become so much interested in the subject of Botany as to desire more
information concerning the growth and reproduction of plants than can
here be given. In Professor Asa Gray's numerous works the additional
information desired may be obtained: "How Plants Grow" contains an
outline for the use of beginners; "The Elements of Botany" is a more
advanced work; while the "Botanical Text Book", in several volumes, will
enable the student to pursue the subject as far as he may wish. In this
small book the barest outline of the parts of flowers and fruit and of
their uses can be given.
[Illustration: Fig. 9.]
FLOWERS.--Parts. The flowers of the Cherry or Apple will show the four
kinds of organs that belong to a complete flower. Fig. 9 represents an
Apple-blossom. The _calyx_ is the outer row of leaves, more or less
united into one piece. The _corolla_ is the row of leaves within the
calyx; it is usually the brightest and most conspicuous part of the
flower. The _stamens_ [Illustration] are the next organs; they are
usually, as in this case, small two-lobed bodies on slender, thread-like
stalks. The enlarged parts contain a dust-like material called
_pollen_. The last of the four kinds of parts is found in the center of
the flower, and is called the _pistil_. It is this part which forms the
fruit and incloses the seed.
The stamens and the pistil are the _essential_ organs of a flower,
because they, and they only, are needed in the formation of seeds. The
pollen from the stamen, acting on the pistil, causes the _ovules_ which
are in the pistil to grow into _seeds_.
The calyx and corolla are called _enveloping organs_, since they
surround and protect the essential parts.
The pieces of which the calyx is composed are called _sepals_. The
Apple-blossom has five sepals.
The pieces that compose the corolla are called _petals_.
KINDS OF FLOWERS.--When the petals are entirely separate from each
other, as in the Apple-blossom, the flower is said to be _polypetalous_;
when they grow together more or less, as in the Catalpa (Fig. 10),
_monopetalous_; and when the corolla is wanting, as in the flowers of
the Oak, _apetalous_.
[Illustration: Fig. 10.]
When all sides of a flower are alike, as in the Apple-blossom, the
flower is _regular_; when one side of the corolla differs from the other
in color, form, or size, as in the Common Locust, or Catalpa, the flower
is _irregular_.
In trees the stamens and pistils are often found in separate flowers; in
that case the blossoms containing stamens are called _staminate_, and
those containing pistils _pistillate_; those that contain both are
called _perfect_. Staminate and pistillate flowers are usually found on
the same tree, as in the Oaks, Birches, Chestnut, etc.; in that case the
plant is said to be _monoecious_, and all trees of this kind produce
fruit. Sometimes, however, the staminate and pistillate flowers are on
separate trees, as in the Willows, which are _dioecious_; and then
only a portion of the trees--those with pistillate flowers--produce
fruit.
ARRANGEMENT OF FLOWERS.--Flowers, either solitary or clustered, grow in
one of two ways; either at the end of the branches, being then called
_terminal_, or in the axils of the leaves, then called _axillary_. The
stem of a solitary flower or the main stem of a cluster is called a
_peduncle_; the stems of the separate blossoms of a cluster are called
_pedicels_. When either the flowers or the clusters are without stems,
they are said to be _sessile_.
_Clusters with Pedicellate Flowers._
_Raceme_, [Illustration] flowers on pedicels of about equal length,
scattered along the entire stem. Locust-tree.
_Corymb_, [Illustration] like a raceme except that the lower flowers
have longer stems, making the cluster somewhat flat-topped; the outer
flowers bloom first. Hawthorn.
_Cyme_, [Illustration] in appearance much like a corymb, but it differs
in the fact that the central flower blooms first. Alternate-leaved
Cornel.
_Umbel_, [Illustration] stems of the separate flowers about equal in
length, and starting from the same point. Garden-cherry.
_Panicle_, [Illustration] a compound raceme. Catalpa.
_Thyrsus_, a compact panicle. Horse-chestnut.
_Clusters with Sessile or Nearly Sessile Flowers._
_Catkin_, [Illustration] bracted flowers situated along a slender and
usually drooping stem. This variety of cluster is very common on trees.
The Willows, Birches, Chestnuts, Oaks, Pines, and many others have their
flowers in catkins.
_Head_, [Illustration] the flowers in a close, usually rounded cluster.
Flowering Dogwood.
FRUIT.--In this book a single fruit will include all the parts that grow
together and contain seeds, whether from a single blossom or a cluster;
there will be no rigorous adherence to an exact classification; no
attempt made to distinguish between fruits formed from a simple pistil
and those from a compound one; nor generally between those formed from a
single and those formed from a cluster of flowers. The fruit and its
general classification, determined by the parts easily seen, is all that
will be attempted.
As stated before, it is hoped that this volume will not end the
student's work in the investigation of natural objects, but that the
amount of information here given will lead to the desire for much more.
_Berry_ will be the term applied to all fleshy fruits with more than one
seed buried in the mass. Persimmon, Mulberry, Holly. The _pome_ or
_Apple-pome_ differs from the berry in the fact that the seeds are
situated in cells formed of hardened material. Apple, Mountain-ash. The
_Plum_ or _Cherry drupe_ includes all fleshy fruits with a single
stony-coated part, even if it contains more than one seed. Peach,
Viburnum, China-tree. In some cases, when there is but one seed in the
flesh and that not stony-coated, it will be called a _drupe-like berry_.
The _dry drupe_ is like the Cherry drupe except that the flesh is much
harder. The fruit of the Walnut, Hickory, and Sumac.
[Illustration: Fig. 11.]
The inner hard-coated parts of these and some others will be called
_nuts_. If the nut has a partial scaly covering, as in the Oaks, the
whole forms an _acorn_. [Illustration] If the coating has spiny hairs,
as in the Chestnut and Beechnut, the whole is a _bur_. The coating in
these cases is an _involucre_. If the coating or any part of the fruit
has a regular place for splitting open, it is _dehiscent_ (Chestnut,
Hickory-nut); if not, _indehiscent_ (Black Walnut).
[Illustration: Fig. 12.]
Dry fruits with spreading, wing-like appendages, as in the Ash (Fig.
11), Maple (Fig. 12), Elm (Fig. 13), and Ailanthus, are called _samaras_
or _keys_.
Dry fruits, usually elongated, containing generally several seeds, are
called _pods_. If there is but one cell and the seeds are fastened along
one side, _Pea-like pods_, or _legumes_. Locust. The term _capsule_
indicates that there is more than one cell. Catalpa, Hibiscus.
[Illustration: Fig. 13.]
All the dry, scaly fruits, usually formed by the ripening of some sort
of catkin of flowers, will be included under the term _cone_. Pine,
Alder, [Illustration] Magnolia. If the appearance of the fruit is not
much different from that of the cluster of flowers, as in the Hornbeams,
Willows, and Birches, the term _catkin_ will be retained for the fruit
also. The scales of a cone may lap over each other; they are then said
to be _imbricated_ or _overlapping_, [Illustration] (Pine); or they may
merely touch at their edges, when they are _valvate_ [Illustration]
(Cypress). When cones or catkins hang downward, they are _pendent_. If
the scales have projecting points, these points are _spines_ if strong,
and _prickles_ if weak. The parts back of the scales are _bracts_; these
often project beyond the scales, when they are said to be _exserted_.
[Illustration] Sometimes the exserted bracts are bent backward; they are
then said to be _recurved_ or _reflexed_.