11 CONTENTS. 



Page. 

 VIII. — Stem, Branch, Leaf, and Cladophyl - - - 119 



Derivation of the stem from the midrib of seaweeds — Genesis 

 of the leaf from the cladophyl — Genesis of the cladophyl 

 from the seaweed frond — The vascular system only a 

 further development of the intercellular system— Dichotomy 

 of fern-veins identical with dichotomy of seaweeds — 

 Degeneration of lobes of leaves into teeth — Angles ..between 

 serrations homologous with axillae — Margins of fronds and 

 leaves, by contraction, become a midrib — The teeth of land- 

 plant leaves descended from teeth of seaweeds — Veins and 

 - sub-veins also found in seaweeds — The leaf a repetition of 

 the stem — Reversion of stem to leaf — Reversion of leaflets to 

 stipels or teeth — Appendicular notes giving examples of 

 atrophy of leaflets. 



IX. — Stem and Rhizome - - - - •• -155 



Asa Gray's definition — Identity of the two — Possible genesis 

 of the rhizome — Advantage of decay of internodes of the 

 rhizome in the struggle for life — The rhizome a feature of 

 the lowest forms of plants — Aerial roots hereditary 

 descendants of rhizome roots. 



X. — Roots and Tendrils - - - - - 163 



Goebel's definition of root — No essential difference between 

 root and stem — Phyllotaxis in roots not needed — On stem it 

 is important — Roots give buds and stems — Stems give roots 

 and buds — Radicle of seed identical with radicle of bud — 

 The disk of seaweeds a rudimentai-y root. 

 Roots and ten-Irils, in many cases, homologous organs — Roots 

 homologous with underground leaves — Advantages of root- 

 budding — The root a rhizome — Nodules of roots of 

 Leguminiferaj said to be caused by microbes, not impossibly 

 they may be the atrophied homologues of the floating bladders 

 on the root-leaves of water plants — Floats of root-leaves of 

 Utricid aria— 'Modules on roots of grasses — Appendicular 

 notes, comparing roots and tendrils, and roots and leaves 

 in different plants. 



XI. — Stipules, Bud-Scales, and Cotyledons - . - 197 



Seaweeds have no traces of stipules — They begin to appear in 

 ferns — Ligules of grasses the tips of stipules — Interpretation 

 of stipules as bud-scales — Glumes of grasses, and spathes of 

 other plants, only stipules — Stipules considered as leaflets 

 left behind — Stipules considered as bud-scales, and convertible 

 into bracts, and even hairs — Stamens have often stipules also 

 — Cotyledons considered as bud-scales or stipules — The 

 starchy cotyledon of endogens a bud-scale — A bud-scale 

 or bract convertible into a spathe-like leaf. 



