Basil King - "The Letter of the Contract"

William Shakespeare - "Der Erste Theil von Koenig Heinrich dem vierten"

John Esten Cooke - "Mohun, or, The Last Days of Lee"

Virginia Bennett - "The Pigeon Tale"

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




In most rusts the teleuto spores are produced late in the summer or
autumn, and remain until the following spring before they germinate.
They are very thick-walled, the walls being dark-colored, so that in
mass they appear black, and constitute the "black-rust" stage
(Fig. 47, _J_). Associated with these, but formed earlier, and
germinating immediately, are often to be found large single-celled
spores, borne on long stalks. They are usually oval in form, rather
thin-walled, but the outer surface sometimes provided with little
points. The contents are reddish, so that in mass they appear of the
color of iron rust, and cause the "red rust" of wheat and other
plants, upon which they are growing.

The classification of the rusts is based mainly upon the size and
shape of the teleuto spores where they are known, as the cluster-cup
and red-rust stages are pretty much the same in all. Of the commoner
genera _Melampsora_, and _Uromyces_ (Fig. 47, _L_ i), have unicellular
teleuto spores; _Puccinia_ (ii) and _Gymnosporangium_, two-celled
spores; _Triphragmium_, three-celled; and _Phragmidium_ (iii), four or
more.

The rusts are so abundant that a little search can scarcely fail to
find some or all of the stages. The cluster-cup stages are best
examined fresh, or from alcoholic material; the teleuto spores may be
dried without affecting them.

Probably the best-known member of the group is the wheat rust
(_Puccinia graminis_), which causes so much damage to wheat and
sometimes to other grains. The red-rust stage may be found in early
summer; the black-rust spores in the stubble and dead leaves in the
autumn or spring, forming black lines rupturing the epidermis.

Probably to be associated with the lower _Basidiomycetes_ are the
large fungi of which _Tremella_ (Fig. 51, _A_) is an example. They are
jelly-like forms, horny and somewhat brittle when dry, but becoming
soft when moistened. They are common, growing on dead twigs, logs,
etc., and are usually brown or orange-yellow in color.

Of the higher _Basidiomycetes_, the toadstools, mushrooms, etc., are
the highest, and any common form will serve for study. One of the most
accessible and easily studied forms is _Coprinus_, of which there are
several species growing on the excrement of various herbivorous
animals. They not infrequently appear on horse manure that has been
kept covered with a glass for some time, as described for _Ascobolus_.
After two or three weeks some of these fungi are very likely to make
their appearance, and new ones continue to develop for a long time.

[Illustration: FIG. 48.--_A_, young. _B_, full-grown fruit of a
toadstool (_Coprinus_), x 2. _C_, under side of the cap, showing the
radiating "gills," or spore-bearing plates. _D_, section across one of
the young gills, x 150. _E_, _F_, portions of gills from a nearly ripe
fruit, x 300. _sp._ spores. _x_, sterile cell. In _F_, a basidium is
shown, with the young spores just forming. _G_, _H_, young fruits,
x 50.]

The first trace of the plant, visible to the naked eye, is a little
downy, white speck, just large enough to be seen. This rapidly
increases in size, becoming oblong in shape, and growing finally
somewhat darker in color; and by the time it reaches a height of a few
millimetres a short stalk becomes perceptible, and presently the whole
assumes the form of a closed umbrella. The top is covered with little
prominences, that diminish in number and size toward the bottom. After
the cap reaches its full size, the stalk begins to grow, slowly at
first, but finally with great rapidity, reaching a height of several
centimetres within a few hours. At the same time that the stalk is
elongating, the cap spreads out, radial clefts appearing on its upper
surface, which flatten out very much as the folds of an umbrella are
stretched as it opens, and the spaces between the clefts appear as
ridges, comparable to the ribs of the umbrella (Fig. 48, _B_). The
under side of the cap has a number of ridges running from the centre
to the margin, and of a black color, due to the innumerable spores
covering their surface (_C_). Almost as soon as the umbrella opens,
the spores are shed, and the whole structure shrivels up and
dissolves, leaving almost no trace behind.

If we examine microscopically the youngest specimens procurable,
freeing from air with alcohol, and mounting in water or dilute
glycerine, we find it to be a little, nearly globular mass of
colorless filaments, with numerous cross-walls, the whole arising
from similar looser filaments imbedded in the substratum (Fig. 48,
_G_). If the specimen is not too young, a denser central portion can
be made out, and in still older ones (Fig. 48, _H_) this central
mass has assumed the form of a short, thick stalk, crowned by a flat
cap, the whole invested by a loose mass of filaments that merge more
or less gradually into the central portion. By the time the spore
fruit (for this structure corresponds to the spore fruit of the
_Ascomycetes_) reaches a height of two or three millimetres, and is
plainly visible to the naked eye, the cap grows downward at the
margins, so as to almost entirely conceal the stalk. A longitudinal
section of such a stage shows the stalk to be composed of a
small-celled, close tissue becoming looser in the cap, on whose
inner surface the spore-bearing ridges ("gills" or _Lamellae_) have
begun to develop. Some of these run completely to the edge of the
cap, others only part way. To study their structure, make
cross-sections of the cap of a nearly full-grown, but unopened,
specimen, and this will give numerous sections of the young gills.
We find them to be flat plates, composed within of loosely
interwoven filaments, whose ends stand out at right angles to the
surface of the gills, forming a layer of closely-set upright cells
(basidia) (Fig. 48, _D_). These are at first all alike, but later
some of them become club-shaped, and develop at the end several
(usually four) little points, at the end of which spores are formed
in exactly the same way as we saw in the germinating teleuto spores
of the cedar rust, all the protoplasm of the basidium passing into
the growing spores (Fig. 48, _E_, _F_). The ripe spores (_E_, _sp._)
are oval, and possess a firm, dark outer wall. Occasionally some of
the basidia develop into very large sterile cells (E, _x_),
projecting far beyond the others, and often reaching the neighboring
gill.

Similar in structure and development to _Coprinus_ are all the large
and common forms; but they differ much in the position of the
spore-bearing tissue, as well as in the form and size of the whole
spore fruit. They are sometimes divided, according to the position of
the spores, into three orders: the closed-fruited (_Angiocarpous_)
forms, the half-closed (_Hemi-angiocarpous_), and the open or
naked-fruited forms (_Gymnocarpous_).

[Illustration: FIG. 49.--_Basidiomycetes_. _A_, common puff-ball
(_Lycoperdon_). _B_, earth star (_Geaster_). _A_, x 1/4. _B_, one-half
natural size.]

Of the first, the puff-balls (Fig. 49) are common examples. One
species, the giant puff-ball (_Lycoperdon giganteum_), often reaches a
diameter of thirty to forty centimetres. The earth stars (_Geaster_)
have a double covering to the spore fruit, the outer one splitting at
maturity into strips (Fig. 49, _B_). Another pretty and common form is
the little birds'-nest fungus (_Cyathus_), growing on rotten wood or
soil containing much decaying vegetable matter (Fig. 50).

[Illustration: FIG. 50.--Birds'-nest fungus (_Cyathus_). _A_, young.
_B_, full grown. _C_, section through _B_, showing the "sporangia"
(_sp._). All twice the natural size.]

In the second order the spores are at first protected, as we have seen
in _Coprinus_, which belongs to this order, but finally become
exposed. Here belong the toadstools and mushrooms (Fig. 51, _B_), the
large shelf-shaped fungi (_Polyporus_), so common on tree trunks and
rotten logs (Fig. 51, _C_, _D_, _E_), and the prickly fungus
(_Hydnum_) (Fig. 51, _G_).

[Illustration: FIG. 51.--Forms of _Basidiomycetes_. _A_, _Tremella_,
one-half natural size. _B_, _Agaricus_, natural size. _C_, _E_,
_Polyporus_: _C_, x 1/2; _E_, x 1/4. _D_, part of the under surface of
_D_, natural size. _F_, _Clavaria_, a small piece, natural size. _G_,
_Hydnum_, a piece of the natural size.]

Of the last, or naked-fruited forms, the commonest belong to the
genus _Clavaria_ (Fig. 51, _F_), smooth-branching forms, usually of a
brownish color, bearing the spores directly upon the surface of the
branches.




CHAPTER XI.

SUB-KINGDOM IV.

BRYOPHYTA.


The Bryophytes, or mosses, are for the most part land plants, though a
few are aquatic, and with very few exceptions are richly supplied with
chlorophyll. They are for the most part small plants, few of them
being over a few centimetres in height; but, nevertheless, compared
with the plants that we have heretofore studied, quite complex in
their structure. The lowest members of the group are flattened,
creeping plants, or a few of them floating aquatics, without distinct
stem and leaves; but the higher ones have a pretty well-developed
central axis or stem, with simple leaves attached.

There are two classes--I. Liverworts (_Hepaticae_), and II. Mosses
(_Musci_).


CLASS I.--THE LIVERWORTS.

One of the commonest of this class, and to be had at any time, is
named _Madotheca_. It is one of the highest of the class, having
distinct stem and leaves. It grows most commonly on the shady side of
tree trunks, being most luxuriant near the ground, where the supply of
moisture is most constant. It also occurs on stones and rocks in moist
places. It closely resembles a true moss in general appearance, and
from the scale-like arrangement of its leaves is sometimes called
"scale moss."

The leaves (Fig. 52, _A_, _B_) are rounded in outline unequally,
two-lobed, and arranged in two rows on the upper side of the stem, so
closely overlapping as to conceal it entirely. On the under side are
similar but smaller leaves, less regularly disposed. The stems branch
at intervals, the branches spreading out laterally so that the whole
plant is decidedly flattened. On the under side are fine, whitish
hairs, that fasten it to the substratum. If we examine a number of
specimens, especially early in the spring, a difference will be
observed in the plants. Some of them will be found to bear peculiar
structures (Fig. 52, _C_, _D_), in which the spores are produced.
These are called "sporogonia." They are at first globular, but when
ripe open by means of four valves, and discharge a greenish brown mass
of spores. An examination of the younger parts of the same plants will
probably show small buds (Fig. 54, _H_), which contain the female
reproductive organs, from which the sporogonia arise.

[Illustration: FIG. 52.--_A_, part of a plant of a leafy liverwort
(_Madotheca_), x 2. _B_, part of the same, seen from below, x 4. _C_,
a branch with two open sporogonia (_sp._), x 4. _D_, a single
sporogonium, x 8.]

On other plants may be found numerous short side branches (Fig. 53,
_B_), with very closely set leaves. If these are carefully separated,
the antheridia can just be seen as minute whitish globules, barely
visible to the naked eye. Plants that, like this one, have the male
and female reproductive organs on distinct plants, are said to be
"dioecious."

A microscopical examination of the stem and leaves shows their
structure to be very simple. The former is cylindrical, and composed
of nearly uniform elongated cells, with straight cross-walls. The
leaves consist of a single layer of small, roundish cells, which,
like those of the stem, contain numerous rounded chloroplasts, to
which is due their dark green color.

The tissues are developed from a single apical cell, but it is
difficult to obtain good sections through it.

The antheridia are borne singly at the bases of the leaves on the
special branches already described (Fig. 53, _A_, _an._). By
carefully dissecting with needles such a branch in a drop of water,
some of the antheridia will usually be detached uninjured, and may
be readily studied, the full-grown ones being just large enough to
be seen with the naked eye. They are globular bodies, attached by a
stalk composed of two rows of cells. The globular portion consists
of a wall of chlorophyll-bearing cells, composed of two layers
below, but single above (Fig. 53, _C_). Within is a mass of
excessively small cells, each of which contains a spermatozoid. In
the young antheridium (_A_, _an._) the wall is single throughout,
and the central cells few in number. To study them in their natural
position, thin longitudinal sections of the antheridial branch
should be made.

[Illustration: FIG. 53.--_A_, end of a branch from a male plant of
_Madotheca_. The small side branchlets bear the antheridia, x 2. _B_,
two young antheridia (_an._), the upper one seen in optical section,
the lower one from without, x 150. _C_, a ripe antheridium, optical
section, x 50. _D_, sperm cells with young spermatozoids. _E_, ripe
spermatozoids, x 600.]

When ripe, if brought into water, the antheridium bursts at the top
into a number of irregular lobes that curl back and allow the mass
of sperm cells to escape. The spermatozoids, which are derived
principally from the nucleus of the sperm cells (53, _D_) are so
small as to make a satisfactory examination possible only with very
powerful lenses. The ripe spermatozoid is coiled in a flat spiral
(53, _E_), and has two excessively delicate cilia, visible only
under the most favorable circumstances.

The female organ in the bryophytes is called an "archegonium," and
differs considerably from anything we have yet studied, but recalls
somewhat the structure of the ooegonium of _Chara_. They are found in
groups, contained in little bud-like branches (54, _H_). In order to
study them, a plant should be chosen that has numbers of such buds,
and the smallest that can be found should be used. Those containing
the young archegonia are very small; but after one has been
fertilized, the leaves enclosing it grow much larger, and the bud
becomes quite conspicuous, being surrounded by two or three
comparatively large leaves. By dissecting the young buds, archegonia
in all stages of growth may be found.

[Illustration: FIG. 54.--_A-D_, development of the archegonium of
_Madotheca_. _B_, surface view, the others in optical section. _o_,
egg cell, x 150. _E_, base of a fertilized archegonium, containing a
young embryo (_em._), x 150. _F_, margin of one of the leaves
surrounding the archegonia. _G_, young sporogonium still surrounded by
the much enlarged base of the archegonium. _h_, neck of the
archegonium. _ar._ abortive archegonia, x 12. _H_, short branch
containing the young sporogonium, x 4.]

When very young the archegonium is composed of an axial row of three
cells, surrounded by a single outer layer of cells, the upper ones
forming five or six regular rows, which are somewhat twisted
(Fig. 54, _A_, _B_). As it becomes older, the lower part enlarges
slightly, the whole looking something like a long-necked flask (_C_,
_D_). The centre of the neck is occupied by a single row of cells
(canal cells), with more granular contents than the outer cells, the
lowest cell of the row being somewhat larger than the others
(Fig. 54, _C_, _o_). When nearly ripe, the division walls of the
canal cells are absorbed, and the protoplasm of the lowest cell
contracts and forms a globular naked cell, the egg cell (_D_, _o_).
If a ripe archegonium is placed in water, it soon opens at the top,
and the contents of the canal cells are forced out, leaving a clear
channel down to the egg cell. If the latter is not fertilized, the
inner walls of the neck cells turn brown, and the egg cell dies; but
if a spermatozoid penetrates to the egg cell, the latter develops a
wall and begins to grow, forming the embryo or young sporogonium.

[Illustration: FIG. 55.--Longitudinal section of a nearly full-grown
sporogonium of _Madotheca_, which has not, however, broken through the
overlying cells, x 25. _sp._ cavity in which the spores are formed.
_ar._ abortive archegonium.]

The first division wall to be formed in the embryo is transverse,
and is followed by vertical ones (Fig. 54, _E_, _em._). As the
embryo enlarges, the walls of the basal part of the archegonium grow
rapidly, so that the embryo remains enclosed in the archegonium
until it is nearly full-grown (Fig. 55). As it increases in size, it
becomes differentiated into three parts: a wedge-shaped base or
"foot" penetrating downward into the upper part of the plant, and
serving to supply the embryo with nourishment; second, a stalk
supporting the third part, the capsule or spore-bearing portion of
the fruit. The capsule is further differentiated into a wall, which
later becomes dark colored, and a central cavity, in which are
developed special cells, some of which by further division into four
parts produce the spores, while the others, elongating enormously,
give rise to special cells, called elaters (Fig. 56, _B_).

[Illustration: FIG. 56.--Spore (_A_) and two elaters (_B_) of
_Madotheca_, x 300.]

The ripe spores are nearly globular, contain chlorophyll and drops
of oil, and the outer wall is brown and covered with fine points
(Fig. 56, _A_). The elaters are long-pointed cells, having on the
inner surface of the wall a single or double dark brown spiral band.
These bands are susceptible to changes in moisture, and by their
movements probably assist in scattering the spores after the
sporogonium opens.

Just before the spores are ripe, the stalk of the sporogonium
elongates rapidly, carrying up the capsule, which breaks through the
archegonium wall, and finally splits into four valves, and discharges
the spores.

There are four orders of the liverworts represented in the United
States, three of which differ from the one we have studied in being
flattened plants, without distinct stems and leaves,--at least, the
leaves when present are reduced to little scales upon the lower
surface.

The first order (_Ricciaceae_) are small aquatic forms, or grow on damp
ground or rotten logs. They are not common forms, and not likely to be
encountered by the student. One of the floating species is shown in
figure 57, _A_.

The second order, the horned liverworts (_Anthoceroteae_), are
sometimes to be met with in late summer and autumn, forms growing
mostly on damp ground, and at once recognizable by their long-pointed
sporogonia, which open when ripe by two valves, like a bean pod
(Fig. 57, _B_).

The third order (_Marchantiaceae_) includes the most conspicuous
members of the whole class. Some of them, like the common liverwort
(_Marchantia_), shown in Figure 57, _F_, _K_, and the giant liverwort
(Fig. 57, _D_), are large and common forms, growing on the ground in
shady places, the former being often found also in greenhouses. They
are fastened to the ground by numerous fine, silky hairs, and the
tissues are well differentiated, the upper surface of the plant having
a well-marked epidermis, with peculiar breathing pores, large enough
to be seen with the naked eye (Fig. 57, _E_, _J_, _K_) Each of these
is situated in the centre of a little area (Fig. 57, _E_), and beneath
it is a large air space, into which the chlorophyll-bearing cells
(_cl._) of the plant project (_J_).

The sexual organs are often produced in these forms upon special
branches (_G_), or the antheridia may be sunk in discs on the upper
side of the stem (_D_, _an._).

[Illustration: FIG. 57.--Forms of liverworts. _A_, _Riccia_, natural
size. _B_, _Anthoceros_ (horned liverwort), natural size. _sp._
sporogonia. _C_, _Lunularia_, natural size, _x_, buds. _D_, giant
liverwort (_Conocephalus_), natural size. _an._ antheridial disc. _E_,
small piece of the epidermis, showing the breathing pores, x 2. _F_,
common liverwort (_Marchantia_), x 2. _x_, cups containing buds. _G_,
archegonial branch of common liverwort, natural size. _H_, two young
buds from the common liverwort, x 150. _I_, a full-grown bud, x 25.
_J_, vertical section through the body of _Marchantia_, cutting
through a breathing pore (_s_), x 50. _K_, surface view of a breathing
pore, x 150. _L_, a leafy liverwort (_Jungermannia_). _sp._
sporogonium, x 2.]

Some forms, like _Marchantia_ and _Lunularia_ (Fig. 57, _C_), produce
little cups (_x_), circular in the first, semicircular in the second,
in which special buds (_H_, _I_) are formed that fall off and produce
new plants.

The highest of the liverworts (_Jungermanniaceae_) are, for the most
part, leafy forms like _Madotheca_, and represented by a great many
common forms, growing usually on tree trunks, etc. They are much like
_Madotheca_ in general appearance, but usually very small and
inconspicuous, so as to be easily overlooked, especially as their
color is apt to be brownish, and not unlike that of the bark on which
they grow (Fig. 57, _L_).


CLASS II.--THE TRUE MOSSES.

The true mosses (_Musci_) resemble in many respects the higher
liverworts, such as _Madotheca_ or _Jungermannia_, all of them having
well-marked stems and leaves. The spore fruit is more highly
developed than in the liverworts, but never contains elaters.

A good idea of the general structure of the higher mosses may be had
from a study of almost any common species. One of the most convenient,
as well as common, forms (_Funaria_) is to be had almost the year
round, and fruits at almost all seasons, except midwinter. It grows in
close patches on the ground in fields, at the bases of walls,
sometimes in the crevices between the bricks of sidewalks, etc. If
fruiting, it may be recognized by the nodding capsule on a long stalk,
that is often more or less twisted, being sensitive to changes in the
moisture of the atmosphere. The plant (Fig. 58, _A_, _B_) has a short
stem, thickly set with relatively large leaves. These are oblong and
pointed, and the centre is traversed by a delicate midrib. The base of
the stem is attached to the ground by numerous fine brown hairs.

The mature capsule is broadly oval in form (Fig. 58, _C_), and
provided with a lid that falls off when the spores are ripe. While the
capsule is young it is covered by a pointed membranous cap (_B_,
_cal._) that finally falls off. When the lid is removed, a fine fringe
is seen surrounding the opening of the capsule, and serving the same
purpose as the elaters of the liverworts (Fig. 58, _E_).

[Illustration: FIG. 58.--_A_, fruiting plant of a moss (_Funaria_),
with young sporogonium (_sp._), x 4. B, plant with ripe sporogonium.
_cal_. calyptra, x 2. _C_, sporogonium with calyptra removed. _op._
lid, x 4. _D_, spores: i, ungerminated; ii-iv, germinating, x 300.
_E_, two teeth from the margin of the capsule, x 50. _F_, epidermal
cells and breathing pore from the surface of the sporogonium, x 150.
_G_, longitudinal section of a young sporogonium, x 12. _sp._ spore
mother cells. _H_, a small portion of _G_, magnified about 300 times.
_sp._ spore mother cells.]

If the lower part of the stem is carefully examined with a lens, we
may detect a number of fine green filaments growing from it, looking
like the root hairs, except for their color. Sometimes the ground
about young patches of the moss is quite covered by a fine film of
such threads, and looking carefully over it probably very small moss
plants may be seen growing up here and there from it.

[Illustration: FIG. 59.--Longitudinal section through the summit of a
small male plant of _Funaria_. _a_, _a'_, antheridia. _p_, paraphysis.
_L_, section of a leaf, x 150.]

This moss is dioecious. The male plants are smaller than the female,
and may be recognized by the bright red antheridia which are formed at
the end of the stem in considerable numbers, and surrounded by a
circle of leaves so that the whole looks something like a flower.
(This is still more evident in some other mosses. See Figure 65, _E_,
_F_.)

The leaves when magnified are seen to be composed of a single layer
of cells, except the midrib, which is made up of several thicknesses
of elongated cells. Where the leaf is one cell thick, the cells are
oblong in form, becoming narrower as they approach the midrib and
the margin. They contain numerous chloroplasts imbedded in the layer
of protoplasm that lines the wall. The nucleus (Fig. 63, _C_, _n_)
may usually be seen without difficulty, especially if the leaf is
treated with iodine. This plant is one of the best for studying the
division of the chloroplasts, which may usually be found in all
stages of division (Fig. 63, _D_). In the chloroplasts, especially
if the plant has been exposed to light for several hours, will be
found numerous small granules, that assume a bluish tint on the
application of iodine, showing them to be starch grains. If the
plant is kept in the dark for a day or two, these will be absent,
having been used up; but if exposed to the light again, new ones
will be formed, showing that they are formed only under the action
of light.

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