of imperfect plants, and exemplified in the Fuci. It 
consists of a slightly indurated pulp, moulded into a 
globule, and invested with an epidermis. Its use seems 
to be superseded by that of the term spore orsporule. 
Hastate. — Halbert-shaped. When the sides of a leaf are pro- 
truded into two lateral spreading points or lobes near 
the base. 
Heart- Wood. — The central and circular layers of the stem of 
dicotyledonous plants, equivalent in its signification 
to the Duramen. 
Helmet. — When the upper lip of a labiate flower is conspicu- 
ously arched, as in Lamium album, it is denoted the 
Helmet — galea. 
Herbs. — Annuals, and plants of a soft texture, are often deno- 
minated herbs, to distinguish them from such as are 
parennial and woody. 
Herbaceous. — Stems which die annually down to the root. 
Herbarium. — No description of a plant is capable of conveying 
an idea of any species so satisfactory as to leave no- 
thing further to be desired with regard to our notion 
of its form. The actual inspection of a specimen is 
indispensable. Hence the necessity imposed upon the 
student of exploring such districts as are within his 
reach, or of having resource to the copia plantarum of 
a Botanic Garden. Nor is even this enough. The 
botanist cannot be always in the field or in the garden 
and yet he may want to see his plants, or some impor- 
tant part of it. Hence, also, the utility of dried spe- 
cimens ; that is, of a Herbarium or Hortus Siccus. 
Hermaphrodites. — Flowers producing both stamens and pis- 
tils in the same individual are Hermaphrodite flowers ; 
and plants producing such flowers are Hermaphrodite 
plants. 
Hilum. — This term denotes the mark that is left on the surface 
of every seed by the natural fracture of the umbilical 
cord. Linnaeus gave it the appellation of the hilum, 
which the term scar translates. 
Hirsute. — When the surface of any part is covered with longish 
hairs. 
Hispid. — When the hairs are short and stiff 1 . 
Hooks. — If the hairs constituting the pubescence of any plant 
are bent backwards at the point, they are then called 
hooks. 
Hooded. — Hooded, when the upper petal of the corolla covers 
the inferior parts, as in Aconitum Napellus. 
Hybrids. — Hybrids are among plants what mules are among 
animals, that is, intermediate productions which have 
sprung from two individuals of two distinct species. 
Hygroscopicity. — This term denotes the property by which 
vegetable tissue, whether dead or alive, tends to absorb 
or to sip up moisture, so as to put itself in due equili- 
brium with the surrounding medium. 
Hymenium. — In the gymnocarpous fungi, the hymenium is the 
organ that bears the seeds or sporules. In Helvella 
it occurs in the shape of an extended membrane; in 
the Agarics, in that of gills ; and in Boletus, in that of 
pores. 
Hypogynous. — When the stamens originate in the receptacle 
and do not adhere either to the ovary or to the petals, 
they are said to be hypogynous. 
Imbricated. — Parts placed one over another like tiles. 
Incomplete Flowers. — When the corolla is wanting, as in 
Morus Nigra. 
Incurvated. — Signifying parts turned inwards. 
Indefinite Inflorescence. — If the principal axis of the in- 
florescence terminates, always, as it extends, in a leaf- 
bud, without passing into the condition of a flower-bud, 
the flower-buds being axillary — such inflorescence is 
said to be indefinite, because you cannot foresee where 
its prolongation is to stop. 
Indusium.— The indusium is a thin and membranaceous in- 
tegument covering the groups of capsules peculiar to 
the Doriferous ferns, and originating for the most part 
in the nerves or veins of the frond, but sometimes also 
in the margin. 
Inferior. — Applied to the corolla, when its receptacle is below 
thegermen; and to the germen, when it is placed 
beneath the calyx or corolla. 
Inflorescence. — The inflorescence, iromflorescere, to flourish, 
a term introduced by Linnaeus, is the peculiar mode 
of aggregation in which flowers are distributed upon 
the plant ; whence it is also called the mode of flowering. 
Insolation. — The exposure of plants to the light of the sun, 
and the vivifying influence which it exerts upon them, 
either directly or in combination with fluids which they 
contain, Dutrochet designates by the term insolation. 
Inter-cellular Passages. — As the great bulk of many plants 
is composed of a cellular system which the vascular 
system merely traverses in a longitudinal direction, it 
will follow, that between the cells, which are in their 
origin of a globular form, certain openings or spaces 
must necessarily exist. They are denominated by 
botanists inter-cellular passages. 
Internode. — The space that intervenes between knot and knot, 
or joint and joint,of stems that are knotted or jointed 
at regular intervals, is denominated the intemode, as 
in the grasses. 
Intervenium. — The area of parenchyma lying between two 
or more veins or veinlets of a leaf, is denominated the 
intervenium. 
Integuments. — Every part or organ of the plant, with the ex- 
ception of the. spongiolae and apex of the pistil, has its 
own peculiar integument or envelope. The stem has 
its bark, the leaf its epidermis ; the flower its calyx or 
corolla or both ; the calyx or corolla their own peculiar 
cuticle ; and the seed its primine and secundine. 
Introsusception. — This term denotes the act of taking in, 
whether of fluids by the root, or of gases by the leaf. 
Involucrum.— The involucrum or wrapper is a species 
of Bracte or floral leaf, or an assemblage of floral 
leaves, peculiar to the tribe of umbelliferous plants, 
situaled at the base either of the general or partial 
umbel, or at the base of both, and regarded as being 
a general or partial involucrum accordingly. It sur- 
rounds the stem or peducle entirely, as in Duucus, 
or by the one half only, as in sEthusa. In the former 
case it is complete ; in the latter dimidiate. If it consist 
of one leaf, it is inonophyllous; if of two leaves, di- 
phyllous ; and if of many leaves, polyphyllous. The 
figure of the leaf or leaves is generally strap-shaped. 
Keel. — The lower petal of a papilionaceous flower, which is 
situated opposite to the standard, and hollowed out in 
the form of a boat, is denominated the keel. 
Kernel. — The seed contained within the shell of stone fruit 
is vulgarly designated by the denomination of the 
kernel. - 
Knots. — The stem of many plants is occasionally disfigured by 
accidental tumours projecting from the surface, and 
forming ultimately what are called knots or bunches. 
They are very common in the oak and elm, and are 
produced perhaps by means of some obstruction in the 
channel of the sap’s motion ; by which the vessels be- 
come convoluted and swell up into a lump. Among the 
branches, knots or bunches are sometimes formed by 
means of a plexus of young shoots, issuing from near- 
ly the same point, and crossing in all directions, and 
finally incorporating together in a sort of natural 
graft, apt to be mistaken at a little distance for a 
wood-pigeon’s nest. They occur often on the branches 
of the Birch-tree, rarely on the Slow-thorn, and are 
known among the peasantry of Scotland by the name 
of Witches’ Knots. They are occasioned, doubtless 
like the bunches of the stem, by some obstruction in 
the channel of the juices of the plant. 
Labiate. — A term first introduced by Tournefort to designate 
his class of plants with lipped flowers; and adopted 
