950 



APPENDIX. BOOK I. 



case with the peripheral ends of fibro-vascular bundles in all plants ; with the vascular 

 elements of the secondary xylem of Conifers and Cycads, and with most of those of the 

 secondary xylem of woody Dicotyledons and of many Monocotyledons ; with the vascular 

 elements of Ferns and their allies (true nessels are known only in Pierh aquilina and in the 

 root oi Athyrium Filix fcemind). See de Bary, Vergleichende Anatomic, p. 172. 



The definition given in the text is not satisfactory : a tracheide is a closed vascular 

 cell ; true 'vessels are formed by the fusion — that is, by the absorption of the intervening 

 septa — of trache'ides. 



Page 118. De Bary (Vergleichende Anatomic) distinguishes the following kinds of 

 prosenchymatous xylem-elements in Dicotyledons (see also p. 651): — 



(i) True Woody Fibres : differing from tracheides in the absence of the internal 

 spirally-fibrous layer of their wall, and in that the pits are narrow, elongated 

 transversely, and oblique ; they contain a small residue of protoplasm, 

 (2) Fibres (secondary wood) : septate or unseptate, of two kinds, 



a. resembling the true woody fibres, but differing from them in that 



they almost always contain starch, and sometimes chlorophyll or 

 tannin ; 



b. shorter fibres, tending to parenchymatous form (hence termed ersatZ' 



fasern or ' intermediate cells '). 

 Page 130, line 13 from the top. Dele the word * cortex.' 



„ line 16 from the top. For ' phloem {K) ' read ' cortex (jR).' 



Page 131, line 20 from the top. For ' secondary cortex' read 'secondary phloem.* 

 Page 132, line 25 from the top. Dele the word 'phloem.' 



Page 135. The cambium which is formed outside the primary xylem-bundles arises 

 in the pericambium. 



Page 136, section (c). The following is to be substituted for the last two para- 

 graphs of this section ; — 



1. The successive rings of bundles originate in the primary cortex: Menispermeae, 



Cycadese, Avicennieae. 



2. They originate in the primary phloem : Phytolacca. 



3. They originate in the secondary phloem: Wistaria^ Bauhmia, Rhynchosia (Legu- 



minosae) ; Securidaca (Polygalaceae) ; Gnetum; Doliocarpus (Dilleniaceae) ; 

 Phytocrene (Olacineae). (See de Bary, Vergleichende Anatomic, 1877.) 



Section (d). The account of the mode of growth of the stems of Bignoniaceae given 

 by de Bary {loc. cit.) differs somewhat from that in the text. According to him four 

 symmetrically placed fibro-vascular bundles of the ring of primary bundles in the stem are 

 from the first larger than the others, all the bundles being connected by a normal cam- 

 bium-ring. When growth in thickness begins it proceeds normally at all points except in 

 the four above-mentioned bundles ; in these the formation of xylem elements is very much 

 smaller than in the adjoining bundles, whereas the formation of bast is much more con- 

 siderable. The cambium layer consequently loses its originally circular outline and 

 becomes deeply infolded where it extends inwards to each of these four bundles. Where 

 it lies radially with respect to the primary bundles, that is, where it is parallel to the 

 circumference, the cambium-layer gives rise to xylem and phloem elements in the normal 

 manner: where the infoldings take place, that is, where it lies upon the sides of the bundles 

 in which the wood has been normally developed, it forms only parenchyma, so that con- 

 siderable masses of cortical tissue are formed between the normally developed bundles^ 

 corresponding in position to the four abnormally developed bundles. 



Page 137, line 2 1 from the bottom. None of the scattered bundles in the pith of 

 Piperaceae, Amarantaceae {Amarantus, Euxolus), or Nyctagineae are cauline : they are leaf- 

 traces (de Bary, Vergl. Anat.). The structure of these abnormal forms will be rendered 

 more intelligible by the following considerations. The primary bundles in the dicotyle- 

 donous stem are in some cases all leaf-traces (e. g. Ricinus, Cucurbita), but more commonly 

 other primary bundles which are cauline are formed between the primary leaf-traces. 



