Henry Blake Fuller - "Bertram Cope's Year"

Albert Leffingwell - "An Ethical Problem"

Major A.R. Calhoon - "How to Get on in the World"

Johann Wolfgang von Goethe - "Roemische Elegien"

Annual Bibliography of Commonwealth Literature 2007
This paper argues that discourses of love in Ghanaian market literature for youth offer a view into complex negotiations of agency and empowerment. Drawing on Deborah Durham's notion of youth as "social `shifters'" and Francis Nyamnjoh's conception of the "interconnectedness" of agency, I take Ghanaian market literature as one specific case of how African literature for youth foregrounds questions of continuity and change as African societies enter into increasingly complex global relations. In this literature for youth, received notions of love, often constructed out of impressions from American pop and hip hop music, carry new notions of agency that compete with existing "domesticated" forms. Authors like Ike Tandoh and Evelyn Tay employ discourses of love to offer youth alternative avenues for empowerment in a context of socio-economic disenfranchizement. In a creative process of "straddling", this writing both reveals and reproduces the contradictions that obtain in youth configurations of agency.

Elements of Structural and Systematic Botany

D >> Douglas Houghton Campbell >> Elements of Structural and Systematic Botany




The flowers open for several days in succession, but only when the sun
is shining. They are visited by numerous insects which carry the
pollen from one flower to another and deposit it upon the stigma,
where it germinates, and the tube, growing down through the long
style, finally reaches the ovules and fertilizes them. Usually only a
comparatively small number of the seeds mature, there being almost
always a number of imperfect ones in each pod. The pod or fruit (_F_)
is full-grown about a month after the flower opens, and finally
separates into three parts, and discharges the seeds. These are quite
large (Fig. 81, _J_) and covered with a yellowish brown outer coat,
and provided with a peculiar, whitish, spongy appendage attaching it
to the placenta. A longitudinal section of a ripe seed (_K_) shows the
very small, nearly triangular embryo (_em._), while the rest of the
cavity of the seed is filled with a white, starch-bearing tissue, the
endosperm.

[Illustration: FIG. 82.--_Erythronium_. _A_, a portion of the wall of
the anther, x 150. _B_, a single epidermal cell from the petal, x 150.
_C_, cross-section of a fibro-vascular bundle of the stem, x 150.
_tr._ vessels. _D_, _E_, longitudinal section of the same, showing the
markings of the vessels, x 150. _F_, a bit of the epidermis from the
lower surface of a leaf, showing the breathing pores, x 50. _G_, a
single breathing pore, x 200. _H_, cross-section of a leaf, x 50.
_st._ a breathing pore. _m_, the mesophyll. _fb._ a vein. _I_,
cross-section of a breathing pore, x 200. _J_, young embryo, x 150.]

A microscopical examination of the tissues of the plant shows them
to be comparatively simple, this being especially the case with the
fibro-vascular system.

The epidermis of the leaf is readily removed, and examination shows
it to be made up of oblong cells with large breathing pores in
rows. The breathing pores are much larger than any we have yet
seen, and are of the type common to most angiosperms. The ordinary
epidermal cells are quite destitute of chlorophyll, but the two
cells (guard cells) enclosing the breathing pore contain numerous
chloroplasts, and the oblong nuclei of these cells are usually
conspicuous (Fig. 82, _G_). By placing a piece of the leaf between
pieces of pith, and making a number of thin cross-sections at right
angles to the longer axis of the leaf, some of the breathing pores
will probably be cut across, and their structure may be then better
understood. Such a section is shown in Figure 82, _I_.

The body of the leaf is made up of chlorophyll-bearing cells of
irregular shape and with large air spaces between (_H_, _m_). The
veins traversing this tissue are fibro-vascular bundles of a type
structure similar to that of the stem, which will be described
presently.

The stem is made up principally of large cells with thin walls,
which in cross-section show numerous small, triangular,
intercellular spaces (_i_) at the angles. These cells contain,
usually, more or less starch. The fibro-vascular bundles (_C_) are
nearly triangular in section, and resemble considerably those of the
field horse-tail, but they are not penetrated by the air channel,
found in the latter. The xylem, as in the pine, is toward the
outside of the stem, but the boundary between xylem and phloem is
not well defined, there being no cambium present. In the xylem are a
number of vessels (_C_, _tr._) at once distinguishable from the
other cells by their definite form, firm walls, and empty cavity.
The vessels in longitudinal sections show spiral and ringed
thickenings. The rest of the xylem cells, as well as those of the
phloem, are not noticeably different from the cells of the ground
tissue, except for their much smaller size, and absence of
intercellular spaces.

The structure of the leaves of the perigone is much like that of the
green leaves, but the tissues are somewhat reduced. The epidermis of
the outer side of the sepals has breathing pores, but these are
absent from their inner surface, and from both sides of the petals.
The walls of the epidermal cells of the petals are peculiarly
thickened by apparent infoldings of the wall (_B_), and these cells,
as well as those below them, contain small, yellow bodies
(chromoplasts) to which the bright color of the flower is due. The
red specks on the base of the perigone leaves, as well as the red
color of the back of the sepals, the stalk, and leaves are due to a
purplish red cell sap filling the cells at these points.

The filaments or stalks of the stamens are made up of very delicate
colorless cells, and the centre is traversed by a single
fibro-vascular bundle, which is continued up through the centre of
the anther. To study the latter, thin cross-sections should be made
and mounted in water. Each of the four sporangia, or pollen sacs, is
surrounded on the outside by a wall, consisting of two layers of
cells, becoming thicker in the middle of the section where the
single fibro-vascular bundle is seen (Fig. 81, _H_). On opening, the
cavities of the adjacent sporangia are thrown together. The inner
cells of the wall are marked by thickened bars, much as we saw in
the pine (Fig. 82, _A_), and which, like these, are formed shortly
before the pollen sacs open. The pollen spores (Fig. 81, _I_) are
large, oval cells, having a double wall, the outer one somewhat
heavier than the inner one, but sufficiently transparent to allow a
clear view of the interior, which is filled with very dense,
granular protoplasm in which may be dimly seen two nuclei (_n_,
_ni._), showing that here also there is a division of the spore
contents, although no wall is present. The spores do not germinate
very readily, and are less favorable for this purpose than those of
some other monocotyledons. Among the best for this purpose are the
spiderwort (_Tradescantia_) and _Scilla_.

Owing to the large size and consequent opacity of the ovules, as
well as to the difficulty of getting the early stages, the
development and finer structure of the ovule will not be discussed
here. The full-grown ovule may be readily sectioned, and a general
idea of its structure obtained. A little potash may be used to
advantage in this study, carefully washing it away when the section
is sufficiently cleared. We find now that the ovule is attached to a
stalk (funiculus) (Fig. 81, _G_, _f_), the body of the ovule being
bent up so as to lie against the stalk. Such an inverted ovule is
called technically, "anatropous." The ovule is much enlarged where
the stalk bends. The upper part of the ovule is on the whole like
that of the pine, but there are two integuments (i, ii) instead of
the single one found in the pine.

As the seed develops, the embryo sac (_G_, _sp._) enlarges so as to
occupy pretty much the whole space of the seed. At first it is
nearly filled with a fluid, but a layer of cells is formed, lining
the walls, and this thickens until the whole space, except what is
occupied by the small embryo, is filled with them. These are called
the "endosperm cells," but differ from the endosperm cells of the
gymnosperms, in the fact that they are not developed until after
fertilization, and can hardly, therefore, be regarded as
representing the prothallium of the gymnosperms and pteridophytes.
These cells finally form a firm tissue, whose cells are filled with
starch that forms a reserve supply of food for the embryo plant when
the seed germinates. The embryo (Fig. 81, _K_, _em._, Fig. 82, _J_),
even when the seed is ripe, remains very small, and shows scarcely
any differentiation. It is a small, pear-shaped mass of cells, the
smaller end directed toward the upper end of the embryo sac.

The integuments grow with the embryo sac, and become brown and hard,
forming the shell of the seed. The stalk of the ovule also enlarges,
and finally forms the peculiar, spongy appendage of the seeds already
noticed (Fig. 81, _J_, _K_).




CHAPTER XVI.

CLASSIFICATION OF THE MONOCOTYLEDONS.


In the following chapter no attempt will be made to give an exhaustive
account of the characteristics of each division of the monocotyledons,
but only such of the most important ones as may serve to supplement
our study of the special one already examined. The classification
here, and this is the case throughout the spermaphytes, is based
mainly upon the characters of the flowers and fruits.

The classification adopted here is that of the German botanist
Eichler, and seems to the author to accord better with our present
knowledge of the relationships of the groups than do the systems that
are more general in this country. According to Eichler's
classification, the monocotyledons may be divided into seven groups;
viz., I. _Liliiflorae_; II. _Enantioblastae_; III. _Spadiciflorae_;
IV. _Glumaceae_; V. _Scitamineae_; VI. _Gynandrae_; VII. _Helobiae_.


ORDER I.--_Liliiflorae_.

The plants of this group agree in their general structure with the
adder's-tongue, which is a thoroughly typical representative of the
group; but nevertheless, there is much variation among them in the
details of structure. While most of them are herbaceous forms (dying
down to the ground each year), a few, among which may be mentioned the
yuccas ("bear grass," "Spanish bayonet") of our southern states,
develop a creeping or upright woody stem, increasing in size from year
to year. The herbaceous forms send up their stems yearly from
underground bulbs, tubers, _e.g._ _Trillium_ (Fig. 83, _A_), or
thickened, creeping stems, or root stocks (rhizomes). Good examples of
the last are the Solomon's-seal (Fig. 83, _B_), _Medeola_ (_C_, _D_),
and iris (Fig. 84 _A_). One family, the yams (_Dioscoreae_), of which
we have one common native species, the wild yam (_Dioscorea villosa_),
have broad, netted-veined leaves and are twining plants, while another
somewhat similar family (_Smilaceae_) climb by means of tendrils at the
bases of the leaves. Of the latter the "cat-brier" or "green-brier" is
a familiar representative.

[Illustration: FIG. 83.--Types of _Liliiflorae_. _A_, _Trillium_, x 1/4.
_B_, single flower of Solomon's-seal (_Polygonatum_), x 1. _C_, upper
part of a plant. _D_, underground stem (rhizome) of Indian cucumber
root (_Medeola_), x 1/2. _E_, a rush (_Juncus_), x 1. _F_, a single
flower, x 2. _A-D_, _Liliaceae_; _E_, _Juncaceae_.]

The flowers are for the most part conspicuous, and in plan like that
of the adder's-tongue; but some, like the rushes (Fig. 83, _E_), have
small, inconspicuous flowers; and others, like the yams and smilaxes,
have flowers of two kinds, male and female.

[Illustration: FIG. 84.--Types of _Liliiflorae_. _A_, flower of the
common blue-flag (_Iris_), x 1/2 (_Iridaceae_). _B_, the petal-like upper
part of the pistil, seen from below, and showing a stamen (_an._).
_st._ the stigma, x 1/2. _C_, the young fruit, x 1/2. _D_, section of the
same, x 1. _E_, diagram of the flower. _F_, part of a plant of the
so-called "gray moss" (_Tillandsia_), x 1/2 (_Bromeliaceae_). _G_, a
single flower, x 2. _H_, a seed, showing the fine hairs attached to
it, x 1. _I_, plant of pickerel-weed (_Pontederia_), x 1/4
(_Pontederiaceae_). _J_, a single flower, x 1. _K_, section of the
ovary, x 4.]

The principal family of the _Liliiflorae_ is the _Liliaceae_, including
some of the most beautiful of all flowers. All of the true lilies
(_Lilium_), as well as the day lilies (_Funkia_, _Hemerocallis_) of
the gardens, tulips, hyacinths, lily-of-the-valley, etc., belong here,
as well as a number of showy wild flowers including several species of
tiger-lilies (_Lilium_), various species of _Trillium_ (Fig. 83, _A_),
Solomon's-seal (_Polygonatum_) (Fig. 83, _B_), bellwort (_Uvularia_),
and others. In all of these, except _Trillium_, the perigone leaves
are colored alike, and the leaves parallel-veined; but in the latter
the sepals are green and the leaves broad and netted-veined. The fruit
of the _Liliaceae_ may be either a pod, like that of the
adder's-tongue, or a berry, like that of asparagus or Solomon's-seal.

Differing from the true lilies in having the bases of the perigone
leaves adherent to the surface of the ovary, so that the latter is
apparently below the flower (inferior), and lacking the inner circle
of stamens, is the iris family (_Iridaceae_), represented by the wild
blue-flag (_Iris versicolor_) (Fig. 84, _A_, _E_), as well as by
numerous cultivated species. In iris the carpels are free above and
colored like the petals (_B_), with the stigma on the under side. Of
garden flowers the gladiolus and crocus are the most familiar
examples, besides the various species of iris; and of wild flowers the
little "blue-eyed grass" (_Sisyrinchium_).

[Illustration: FIG. 85.--_Enantioblastae_. _A_, inflorescence of the
common spiderwort (_Tradescantia_), x 1/2 (_Commelyneae_). _B_, a single
stamen, showing the hairs attached to the filament, x 2. _C_, the
pistil, x 2.]

The blue pickerel-weed (_Pontederia_) is the type of a family of which
there are few common representatives (Fig. 84, _I_, _K_).

The last family of the order is the _Bromeliaceae_, all inhabitants of
the warmer parts of the globe, but represented in the southern states
by several forms, the commonest of which is the so-called "gray moss"
(_Tillandsia_) (Fig. 84, _F_, _H_). Of cultivated plants the pineapple,
whose fruit consists of a fleshy mass made up of the crowded fruits
and the fleshy flower stalks, is the best known.


ORDER II.--_Enantioblastae_.

The second order of the monocotyledons, _Enantioblastae_, includes very
few common plants. The most familiar examples are the various species
of _Tradescantia_ (Fig. 88), some of which are native, others exotic.
Of the cultivated forms the commonest is one sometimes called
"wandering-jew," a trailing plant with zigzag stems, and oval, pointed
leaves forming a sheath about each joint. Another common one is the
spiderwort already referred to. In this the leaves are long and
pointed, but also sheathing at the base. When the flowers are showy,
as in these, the sepals and petals are different, the former being
green. The flowers usually open but once, and the petals shrivel up as
the flower fades. There are four families of the order, the spiderwort
belonging to the highest one, _Commelyneae_.


ORDER III.--_Spadiciflorae_.

The third order of the monocotyledons, _Spadiciflorae_, is a very large
one, and includes the largest and the smallest plants of the whole
sub-class. In all of them the flowers are small and often very
inconspicuous; usually, though not always, the male and female flowers
are separate, and often on different plants. The smallest members of
the group are little aquatics, scarcely visible to the naked eye, and
of extremely simple structure, but nevertheless these little plants
produce true flowers. In marked contrast to these are the palms, some
of which reach a height of thirty metres or more.

The flowers in most of the order are small and inconspicuous, but
aggregated on a spike (spadix) which may be of very large size. Good
types of the order are the various aroids (_Aroideae_), of which the
calla (_Richardia_) is a very familiar cultivated example. Of wild
forms the sweet-flag (_Acorus_), Jack-in-the-pulpit (_Arisaema_)
(Fig. 86, _A_, _D_), skunk-cabbage (_Symplocarpus_), and wild calla
may be noted. In _Arisaema_ (Fig. 86, _A_) the flowers are borne only
on the base of the spadix, and the plant is dioecious. The flowers are
of the simplest structure, the female consisting of a single carpel,
and the male of four stamens (_C_, _D_). While the individual flowers
are destitute of a perigone, the whole inflorescence (cluster of
flowers) is surrounded by a large leaf (spathe), which sometimes is
brilliantly colored, this serving to attract insects. The leaves of
the aroids are generally large and sometimes compound, the only
instance of true compound leaves among the monocotyledons (Fig. 86,
_B_).

[Illustration: FIG. 86.--Types of _Spadiciflorae_. _A_, inflorescence
of Jack-in-the-pulpit (_Arisaema_, _Aroideae_). The flowers (_fl._) are
at the base of a spike (spadix), surrounded by a sheath (spathe),
which has been cut away on one side in order to show the flowers, x 1/2.
_B_, leaf of the same plant, x 1/4. _C_, vertical section of a female
flower, x 2. _D_, three male flowers, each consisting of four stamens,
x 2. _E_, two plants of a duck-weed (_Lemna_), the one at the left is
in flower, x 4. _F_, another common species. _L_, _Trisulea_, x 1.
_G_, male flower of _E_, x 25. _H_, optical section of the female
flower, showing the single ovule (_ov._), x 25. _I_, part of the
inflorescence of the bur-reed (_Sparganium_), with female flowers, x 1/2
(_Typhaceae_). _J_, a single, female flower, x 2. _K_, a ripe fruit,
x 1. _L_, longitudinal section of the same. _M_, two male flowers,
x 1. _N_, a pond-weed (_Potomogeton_), x 1 (_Naiadaceae_). _O_, a
single flower, x 2. _P_, the same, with the perianth removed, x 2.
_Q_, fruit of the same, x 2.]

Probably to be regarded as reduced aroids are the duck-weeds
(_Lemnaceae_) (Fig. 86, _F_, _H_), minute floating plants without any
differentiation of the plant body into stem and leaves. They are
globular or discoid masses of cells, most of them having roots; but
one genus (_Wolffia_) has no roots nor any trace of fibro-vascular
bundles. The flowers are reduced to a single stamen or carpel (Figs.
_E_, _G_, _H_).

The cat-tail (_Typha_) and bur-reed (_Sparganium_) (Fig. 86, _I_, _L_)
are common representatives of the family _Typhaceae_, and the
pond-weeds (_Naias_ and _Potomogeton_) are common examples of the
family _Naiadeae_. These are aquatic plants, completely submerged
(_Naias_), or sometimes partially floating (_Potomogeton_). The latter
genus includes a number of species with leaves varying from linear
(very narrow and pointed) to broadly oval, and are everywhere common
in slow streams.

The largest members of the group are the screw-pines (_Pandaneae_) and
the palms (_Palmae_). These are represented in the United States by
only a few species of the latter family, confined to the southern and
southwestern portions. The palmettoes (_Sabal_ and _Chamaerops_) are
the best known.

Both the palms and screw-pines are often cultivated for ornament, and
as is well known, in the warmer parts of the world the palms are among
the most valuable of all plants. The date palm (_Phoenix dactylifera_)
and the cocoanut (_Cocos nucifera_) are the best known. The apparently
compound ("pinnate" or feather-shaped) leaves of many palms are not
strictly compound; that is, they do not arise from the branching of an
originally single leaf, but are really broad, undivided leaves, which
are closely folded like a fan in the bud, and tear apart along the
folds as the leaf opens.

Although these plants reach such a great size, an examination of the
stem shows that it is built on much the same plan as that of the other
monocotyledons; that is, the stem is composed of a mass of soft,
ground tissue through which run many small isolated, fibro-vascular
bundles. A good idea of this structure may be had by cutting across a
corn-stalk, which is built on precisely the same pattern.


ORDER IV.--_Glumaceae_.

The plants of this order resemble each other closely in their habit,
all having long, narrow leaves with sheathing bases that surround the
slender, distinctly jointed stem which frequently has a hard, polished
surface. The flowers are inconspicuous, borne usually in close spikes,
and destitute of a perigone or having this reduced to small scales or
hairs. The flowers are usually surrounded by more or less dry leaves
(glumes, paleae) which are closely set, so as to nearly conceal the
flowers. The flowers are either hermaphrodite or unisexual.

[Illustration: FIG. 87.--Types of _Glumaceae_. _A_, a sedge, _Carex_
(_Cyperaceae_). [Male], the male; [Female], the female flowers, x 1/2.
_B_, a single male flower, x 2. _C_, a female flower, x 2. _D_,
fruiting spike of another _Carex_, x 1/2. _E_, a single fruit, x 1. _F_,
the same, with the outer envelope removed, and slightly enlarged. _G_,
section of _F_, x 3. _em._ the embryo. _H_, a bulrush, _Scirpus_
(_Cyperaceae_), x 1/2. _I_, a single spikelet, x 2. _J_, a single flower,
x 3. _K_, a spikelet of flowers of the common orchard grass,
_Dactylis_ (_Gramineae_), x 2. _L_, a single flower, x 2. _M_, the base
of a leaf, showing the split sheath encircling the stem, x 1. _N_,
section of a kernel of corn, showing the embryo (_em._), x 2.]

There are two well-marked families, the sedges (_Cyperaceae_) and the
grasses (_Gramineae_). The former have solid, often triangular stems,
and the sheath at the base of the leaves is not split. The commonest
genera are _Carex_ (Fig. 87, _A_, _G_) and _Cyperus_, of which there
are many common species, differing very little and hard to
distinguish. There are several common species of _Carex_ which blossom
early in the spring, the male flowers being quite conspicuous on
account of the large, yellow anthers. The female flowers are in
similar spikes lower down, where the pollen readily falls upon them,
and is caught by the long stigmas. In some other genera, _e.g._ the
bulrushes (_Scirpus_) (Fig. 87, _H_), the flowers are hermaphrodite,
_i.e._ contain both stamens and pistils. The fruit (Fig. 87, _F_) is
seed-like, but really includes the wall of the ovary as well, which is
grown closely to the enclosed seed. The embryo is small, surrounded by
abundant endosperm (Fig. 87, _G_). Very few of the sedges are of any
economic importance, though one, the papyrus of Egypt, was formerly
much valued for its pith, which was manufactured into paper.

The second family, the grasses, on the contrary, includes the most
important of all food plants, all of the grains belonging here. They
differ mainly from the sedges in having, generally, hollow,
cylindrical stems, and the sheath of the leaves split down one side;
the leaves are in two rows, while those of the sedges are in three.
The flowers (Fig. 87, _L_) are usually perfect; the stigmas, two in
number and like plumes, so that they readily catch the pollen which is
blown upon them. A few, like the Indian corn, have the flowers
unisexual; the male flowers are at the top of the stem forming the
"tassel," and the female flowers lower down forming the ear. The
"silk" is composed of the enormously lengthened stigmas. The fruits
resemble those of the sedges, but the embryo is usually larger and
placed at one side of the endosperm (_N_, _em._).

While most of the grasses are comparatively small plants, a few of
them are almost tree-like in their proportions, the species of bamboo
(_Bambusa_) sometimes reaching a height of twenty to thirty metres,
with stems thirty to forty centimetres in diameter.


ORDER V.--_Scitamineae_.

[Illustration: FIG. 88.--_Scitamineae_. _A_, upper part of a flowering
plant of Indian shot (_Canna_), much reduced in size (_Cannaceae_).
_B_, a single flower, x 1/2. _C_, the single stamen (_an._), and
petal-like pistil (_gy._), x 1. _D_, section of the ovary, x 2. _E_,
diagram of the flower. The place of the missing stamens is indicated
by small circles. _F_, fruit, x 1/2. _G_, section of an unripe seed.
_em._ embryo. _p_, perisperm, x 2.]

The plants of this order are all inhabitants of the warmer parts of
the earth, and only a very few occur within the limits of the United
States, and these confined to the extreme south. They are extremely
showy plants, owing to their large leaves and brilliant flowers, and
for this reason are cultivated extensively. Various species of _Canna_
(Fig. 88) are common in gardens, where they are prized for their
large, richly-colored leaves, and clusters of scarlet, orange, or
yellow flowers. The leafy stems arise from thick tubers or root
stocks, and grow rapidly to a height of two metres or more in the
larger species. The leaves, as in all the order, are very large, and
have a thick midrib with lateral veins running to the margin. The
young leaves are folded up like a trumpet. The flowers are irregular
in form, and in _Canna_ only a single stamen is found; or if more are
present, they are reduced to petal-like rudiments. The single, perfect
stamen (Fig. 88, _C_, _an._) has the filament broad and colored like
the petals, and the anther attached to one side. The pistil (_gy._) is
also petal-like. There are three circles of leaves forming the
perigone, the two outer being more or less membranaceous, and only the
three inner petal-like in texture. The ovary (_o_) is inferior, and
covered on the outside with little papillae that afterward form short
spines on the outside of the fruit (_F_).

The seeds are large, but the embryo is very small. A section of a
nearly ripe seed shows the embryo (_em._) occupying the upper part of
the embryo sac which does not nearly fill the seed and contains no
endosperm. The bulk of the seed is derived from the tissue of the body
of the ovule, which in most seeds becomes entirely obliterated by the
growth of the embryo sac. The cells of this tissue become filled with
starch, and serve the same purpose as the endosperm of other seeds.
This tissue is called "perisperm."

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