622 



PHANEROGAMS. 



produces only one or a pair of opposite lateral shoots, and the branching is therefore 

 distinctly cymose, sympodial, or, as in Lemna irisulca^ dichasial. 



Besides the formation of shoots by the branching of the axis, adventitious 

 shoots also sometimes occur on leaves which perform the function of gemmae ; 

 as for instance on the margins of the leaves of Hyacitilhus Pouzolsii and some 

 Orchids (Doll, Flora, p. 348)^ The large gemmae which appear very regularly 

 at the point of junction of the leaf-stalk and lamina, and at the base of the lamina 

 of Atherurus krnatus, are especially striking. The small bulbs on the stem of 



Fig. 422.— The underground part of a flowering plant of Colchicum autiannale : A seen in front and from without, k 

 the conn, s' , s" cataphyllary leaves embracing the flower-stalk, 7uk its base from which proceed the roots 7v ; B longitudinal 

 section, hhs. brown skin which envelopes all the underground parts of the plant, st the flower- and leaf-stalk of the 

 previous year which has died down, its swollen basal portion fc only remaining as a reservoir of food-materials for the 

 new plant now in flower. The new plant is a lateral shoot from the base of the corm fc, consisting of the axis from the base 

 of which proceed the roots ■»', and the middle part of which (k') swells up in the next year into a corm, the old corm k 

 disappearing ; the axis bears the sheath-leaves s, s', s" and the foliage-leaves I', I" ; the flowers b. b' are placed in the 

 axils of the uppermost foliage-leaves, the axis itself terminating amongst the flowers. The foliage leaves are still small 

 at the time of flowering ; in the next spring they emerge from the ground together with the fruits ; the portion of the 

 axis k then swells up into the new corm, on which the axillary bud k'' developes into the new flowering plant, while the 

 sheath of the lowermost foliage-leaf is changed into the brown enveloping skin. 



^ [On the buds developed on the leaves of Malaxis which exhibit a striking resemblance to the 

 ovules of Orchideoe, see Dickie, Journ. Linn. Soc. vol. xiv. pp. i and 180. Dr. Dickie considers the 

 structure of these buds to favour the theory that the ovule is homologous to a bud, the nucellus-like 

 body of the bud corresponding to an axis. See also Henslow on Malaxis, Mag. Nat. Hist. vol. I. 

 1829, pp. 441, 442.] 



