Vill INTRODUCTION TO BOTANY. 
62. An Inflorescenceis 
a Spike, or spicate, when the flowers are sessile along a single unbranched 
axis, called the rachis. Catkin is the name given to the spicate inflores- 
cence of several trees whose flowers are reduced to scaly bracts or are 
very imperfect ; as in the oak, willow, &c. Spadix is a fleshy spike 
round which is rolled a single large bract, or spathe, as in the arum plant 
(Richardia Ethiopica). The inflorescence of a Palm is usually a branch- 
ing spadix. : P 
a Raceme, or racemose, when the flowers are borne on pedicels along a single 
unbranched axis, also often called the rachis. 
a Panicle, or paniculate, when the axis is divided into branches, each bearing 
two or more flowers. 
a Head or capitate, when several sessile or sub-sessile flowers are collected 
into a compact, head-like cluster. The short, flat, or conical axis on 
which the flowers of a head or capitulum are seated is called the recep- 
tacle: a term also given to the torus or thalamium of a single flower. 
an Umbel, or wmbellate, when several branches or pedicels spring from the 
same (apparent) point, 7.e., from an azis reduced to a point. (It is 
essentially the same as a raceme with the axis aborted ; or as a head, 
with long-stalked flowers). An wmbel is said to be simple, when each of 
its branches or rays supports a single flower ; compound, when each ray 
supports a partial umbel, or wmbellule. 
a Corymb or corymbose, when the branches or pedicels starting from several 
sco on a short, but not aborted axis, all attain nearly the same level. 
It is a flat-topped or fastigiate panicle or short raceme. 
a Cyme or cymose inflorescence is a centrifugal panicle, and is frequently 
. The terminal flower opens first. The lateral branches, 
successively developed, are usually forked (dichotomous or trichotomous). 
Sometimes after the first forking the branches are no longer divided, but 
produce a succession of pedicels on the upper side, forming apparently 
unilateral racemes ; but they differ from true racemes by the pedicels 
springing, not from the axil of the bract, but from a point opposite its 
insertion or above or below it. This variety, called a scorpiord-cyme, is, 
found in Drosera, the Boraginee, and many other plants ; when young 
the branches are frequently rolled back at the top like the tail of a scor- 
pion, whence the name. 
63. Bracts are generally placed singly under each branch of the inflorescence, 
and under each pedicel ; bracteoles are usually two, one on each side, on the pedicel, 
or close under the flower, or on the calyx itself: but bracts are also frequently — 
scattered along the floral branches without axillary pedicels, 
64. When several bracts are collected in a whorl, or are so close together as to 
appear whorled, or are closely imbricated round the base of a head of flowers or an - 
umbel, they are collectively called an Involucre. The bracts composing an invo- 
lucre are variously termed, according to their appearance, leaves, leajlets, bracts, or 
scales. Pale or chaff of the receptacle, are the inner scale-like bracts of compo- 
sites, grasses, and some other plants, when of a thin, yet rigid substance, usually 
narrow, and pale or translucent. (lumes are the bracts of sedges and grasses. 
§ 8. The Flower. 
65. A flower is a terminal bud, enclosing the organs of reproduction by seed. An 
unopened flower is called a flower-bud, or alabastrus; and the period between the 
oe of a —— — pg ei gio of withering is its anthesis, 
- The parts of a flower or organs are— Ist, the perianth, consisting either 
wey Pagar if in - — whorl ; or 4 calyx and corolla, if in a double whorl; _ 
2nd, amens, or organs ; the pistil, which contains the ovules, or 
ns of the future seeds. : ; cae ich a 
67. A complete flower is one in which the calyx, corolla, stamens, and pistil are 
all present ; a perfect flower is one in which all organs, or such of them as are 
present, are capable of performing their several functions. An incomplete flower is one 
in which some of the floral organs are wanting ; and an imperfect flower one in which 
some organs are 60 altered as to be incapable of performing their proper 
