PHA NER OGAMS. a , i 



parts in a morphological sense are the embryo and the endosperm, which are pro- 

 duced in the ovule. 



The Inflorescence. When a shoot which has previously formed a large number of 

 foliage-leaves terminates in a flower, the flower is said to be terminal ; if, on the other 

 hand, a lateral shoot developes at once into a flower, with one or at most a few bracteoles 

 beneath it, the flower is termed lateral. Sometimes the first primary axis which proceeds 

 from the embryo terminates in a flower ; but more often the axis continues to grow, 

 or its growth comes to an end, without forming a flower ; it is only lateral shoots of 

 the first, second, or a higher order that terminate in flowers. In the first case the 

 plant may be termed, in reference to the formation of its flowers, uniaxial, in the other 

 cases bi-, tri-axial, &c. When a plant produces only terminal flowers, or when the 

 lateral flowers spring from the axils of single large foliage-leaves, they are said to be 

 solitary. When, on the other hand, the flowering branchlets are densely crowded, 

 and the leaves within this region of ramification are smaller and of a different form 

 and colour from the others, or are entirely absent, an Infloresceyice arises in the nar- 

 rower sense of the term, usually sharply diflferentiated from the vegetative region of 

 the plant, and not unfrequently assuming very peculiar forms which require a special 

 terminology. This occurs however only rarely among Gymnosperms, the formation 

 of nniltifloral inflorescences of peculiar form being characteristic of the more highly 

 developed structure of Angiosperms ; and it will therefore be convenient to defer a 

 more detailed classification and definition of inflorescences until we are treating of 

 that class. 



With reference also to the Forms of Tissue, one point only need be mentioned here, 

 in which Gymnosperms and Angiosperms agree. The Fibro-'vascular Bundles of Phane- 

 rogams exhibit the characteristic peculiarity that every bundle which bends outwards to 

 a leaf is only the upper arm of a bundle which runs downwards into the stem ; in other 

 words, tve have here ' common ' bundles, each of which has one arm that ascends and 

 bends out into the leaf, and another which descends and runs down into the stem ; the 

 latter is called by Hanstein the ' inner leaf-trace' [see p. 134]. In the most simple cases 

 {e.g. in most Conifera^) only one bundle bends out into each leaf; but when the inser- 

 tion of the leaf is broad, or the leaf is large and strongly developed, a larger number 

 of bundles pass from the stem into the leaf, in which they ramify when the lamina is 

 broad. The bundles are usually thicker at the spot where they pass from the stem 

 into the leaf than lower down in their course. Each bundle of this kind may pass 

 downwards through only one internode or through several; in the latter case an 

 internode with several leaves standing above it contains the lower parts of bundles 

 which bend outwards above into leaves of diff'erent height and diff'erent age. The 

 descending foliar bundle seldom has its lower extremity free; it is usually attached 

 laterally to the middle or upper part of a lower (or older) bundle. This may take place 

 by the bundle splitting below into two arms which anastomose with the lower bundles ; 

 or the thin ends of the descending bundles may intercalate themselves between the 

 upper parts of older foliar bundles ; or each bundle may bend right or left and become 

 finally joined laterally to a lower bundle. In this manner the foliar bundles, originally 

 isolated, are united laterally in the stem into a connected system ; and this, when 

 copiously developed, gives the impression of having arisen by branching, whereas it arises 

 in fact from the coalescence of separate portions originally distinct. 



Besides the descending arms of the common bundles, others may however occur in 

 the stem of Phanerogams ; first of all net-works (as in Grasses) or girdle-like reticula- 

 tions (as in Rubiace^ or Sambucus) are frequently formed in the nodes of the stem 

 by horizontal bundles. Furthermore, longitudinal bundles may become diflferentiated in 

 the stem, which have nothing to do with the leaves; and the mode of formation of 

 these 'cauline bundles' may vary greatly. They originate either at an early period m 

 the primary meristem of the stem, immediately after the foliar bundles and m the pith 

 (as in Begoniaceae, Piperacese, and Cycadeae), or only at a much later period in the 



