352 THE CROWFOOT FAMILY 



bered as affording other examples already discussed in 

 Chapter V. 



104. Plant formulas. We may be helped in summing up what 

 we have learned from our various examples if we express their 

 most significant structural characteristics by means of symbols 

 arranged in a sort of tabular view as on page 353. 



At the beginning of the formulas there given, the signs Q,'^,^ , 

 -J5 , '^ are used respectively for annuals, perennial herbs, woody plants, 

 small shrubs, and vines, as already explained (p. 333). A comma indi- 

 cates an alternative, and is to be read "or." Thus in the formula 

 of Pceonia we have "21,:;^, reading "perennial herbs or low shrubs." 

 These signs since they apply to the plants as a whole come first in 

 the formula. The letters which follow stand for various parts: 

 L for leaves; l, leaflets; I, inflorescence; i, secondary inflorescence; 

 B, bracts; b, bractlets; S, sepals; P, petals; FA, stamens (filaments 

 with anthers) ; F, staminodes (filaments without anthers) ; CE, carpels 

 (carpellary leaves with ovules, i. e., egg-sac members); E, ovules 

 well developed; e, rudimentary ovules; T, torus; C, carpels ripened 

 into pericarps; E, seeds; G, embryo (germ) ; N, albumen (nutriment). 



When the leaves are alternate, as in all the genera except Clematis, 

 this is expressed by Li/i which signifies that there is a single leaf at 

 each internode. In the exception noted L'-/2 means that the leaves 

 are opposite, i. e., two at a node. Palmate nervation is shown by 

 the asterisk *, ternate by the dagger sign f, and pinnate by the 

 double dagger J, which, as will be noticed, suggest by their form the 

 arrangement of nerves they each represent. That a leaf is com- 

 pound is implied by the presence of leaflets indicated b}'^ the small l. 



In the formulas of Anemone and Clematis this shows that the 

 leaves are but once-compound, while in the Pieonia formula l^-^ 

 means that the leaves are once to thrice-compound, while iJ+ in the 

 Aquilegia and Aetata formulas stands for decompound. 



When the inflorescence is of the indeterminate t^npe an inverted 

 comma follows the I as in the Aconitum and Actsea formulas; and 

 when of the determinate type, as in the other examples, an inverted 

 period is used. A solitary terminal flower, as in Pseonia and Nigella, 

 is indicated by I'l. Where, as in Caltha, Anemone, and Clematis, 

 additional flowers may appear forming a cymose cluster, I'l + is 

 used. When the plant has onl}^ solitary axillary flowers like ]\Iyo- 

 surus the expression becomes I'l. A cymose cor.ymb, as of Aquilegia, 

 is represented by TV; while a raceme of the botryose type, as in 

 Aconitum and Aetata, has I", the short and the long oblique lines 

 standing respectively for short and long pedicels. The presence of 

 a small i, as in the formula of Clematis, implies a compound cluster. 

 In this case_ it is shown to be of paniculate form because of the 

 relatively short pedicels. Where the type and form of inflorescence 

 varies as in Ranunculus, their special signs may be omitted. The 



