APPENDIX ON PRACTICAL WORK. 1 49 



herbaceous stem proves nothing. A rhizome (p. 26) belongs to a peren- 

 nial. A dilated succulent tap-root generally indicates a biennial. 



II. Root. — If an underground structure possesses scale leaves, buds, 

 or chlorophyll, it does not belong to the root at all, but to the stem. 



III. Stem. — See last paragraph. In the examination of corms and 

 bulbs, note the appearances made by cutting through them in the 

 middle ; (a.) from above downwards, (b.) across. The difference (p. 26) 

 between the two kinds of structure will readily be seen, and buds can 

 also be detected in the typical situations. As examples of bulb, take 

 onion, lily, and hyacinth ; for conns, examine crocus, colchicum, and 

 cyclamen (sold as "bulbs" by florists). 



IV. Foliage Leaf : — 



1. Composition. — Remember that stipules may fall off early (p. 64), 

 and therefore do not put exstipulate unless young leaves are present. 

 Say rather, " apparently exstipulate." 



Note that there may be great variation in the foliage leaves of the 

 same plant. 



2. Arrange 1 ne nt. — Satisfy yourself that so-called "radical" leaves 

 really arise from a condensed lower part of the stem. Take, for 

 example, an entire daisy plant, and halve it with a knife. The crowded 

 nodes can then be made out. No root possesses nodes and internodes. 

 Remember that adventitious root-fibres are, as a rule, given off from all 

 underground structures. 



Arrangement in Bud. — Relative arrangement of leaves is seen by 

 cutting across (footnote, p. 84). The arrangement of individual leaves 

 (footnote, p. 49) is partly shown by the same method, partly by cutting 

 through the bud longitudinally, and also by separating the individual 

 leaves. The following are examples of the terms used for foliage 

 leaves : — Imbricate, grasses and sedges ; plaited, maple and currant ; 

 conduplicate, bean and oak ; inflexed, tulip-tree ; convolute, cherry and 

 apricot ; involute, violet and waterlily ; revolute, sorrel and rosemary ; 

 circinate, sundew and ferns. The remaining terms in the footnotes are 

 used in the case of flower buds. Note if the young leaves are protected 

 by down (p. 67). 



Phyllotaxis. — To determine the divergence (p. 50) take any leaf, call 

 it 1, and mark it. Then find the next leaf which comes immediately 

 above it, say the 9th. 9-1=8, the number of leaves in the cycle, and 

 denominator of the divergence fraction. Verify this by determining 

 the number of ranks or longitudinal leaf-rows. This should be 8. 

 Suppose also that it is necessary to go three times round the stem in 

 passing from 1 to 9. This gives the numerator of the fraction, which 

 is therefore f (compare fig. 9). 



V. Scale Leaf. — In the case of the bud, try to find the relation 

 between the scales and young foliage leaves, and prove what region 

 they represent (p. 64). Observe whether blastocolla is present. 



In the case of underground scale-leaves, observe whether thickened 

 as storage organs. Look for axillary buds, e.g., in a potato. 



VI. Inflorescence and Bracts. — Note the position of the youngest 

 flowers. If these are at end (figs. 31 and 32) or in centre (e.g., daisy 

 and carrot), the inflorescence is centripetal, indefinite, or racemose. If 



