These three are the essential parts of a stem. But {242} besides these, it has, when largely developed, a permanent form: namely, IV. THE TRUNK.--A non-advancing mass of collected stem, arrested at a given height from the ground 139 /# The stems of annual plants are either leafy, as of a thistle, or bare, sustaining the flower or flower-cluster at a certain height above the ground. Receiving therefore these following names:--- #/ V. THE VIRGA.--The leafy stem of an annual plant, not a grass, yet growing upright 147 VI. THE VIRGULA.--The leafless flower-stem of an annual plant, not a grass, as of a primrose or dandelion 147 VII. THE FILUM.--The running stem of a creeping plant /# It is not specified in the text for use; but will be necessary; so also, perhaps, the Stelechos, or stalk proper (26), the branched stem of an annual plant, not a grass; one cannot well talk of the Virga of hemlock. The 'Stolon' is explained in its classical sense at page 158, but I believe botanists use it otherwise. I shall have occasion to refer to, and complete its explanation, in speaking of bulbous plants. #/ VIII. THE CAUDEX.--The essentially ligneous and compact part of a stem 149 {243} /# This equivocal word is not specified for use in the text, but I mean to keep it for the accumulated stems of inlaid plants, palms, and the like; for which otherwise we have no separate term. #/ IX. THE AVENA.--Not specified in the text at all; but it will be prettier than 'baculus,' which is that I had proposed, for the 'staff' of grasses. See page 179. /# These ten names are all that the student need remember; but he will find some interesting particulars respecting the following three, noticed in the text:--- #/ STIPS.--The origin of stipend, stupid, and stump 148 STIPULA.--The subtlest Latin term for straw 148 CAULIS (Kale).--The peculiar stem of branched eatable vegetables 149 CANNA.--Not noticed in the text; but likely to be sometimes useful for the stronger stems of grasses. III. THE LEAF. Derivation of word 26 The Latin form 'folium' 41 The Greek form 'petalos' 42 Veins and ribs of leaves, to be usually summed under the term 'rib' 44 Chemistry of leaves 46 {244}