622 
PHANEROGAMS. 
produces only one or a pair of opposite lateral shoots, and the branching is therefore 
distinctly cymose, sympodial, or, as in Lemna trisuka, 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 Hyacinthus Pouzohn 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 terriatus^ are especially striking. The small bulbs on the stem of 
Fig. 422. — The underground part of a flowering' plant of Colchicum atciumnale : A seen in front and from without, k 
the conn, s' , s" cataphyllary leaves embracing the flower-stalk, -wh its base from which proceed the roots w ; B longitudinal 
section, h h a 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 k 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 k, consisting of the axis from the base 
of which proceed the roots -a', 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 /" ; the flowers & 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 Orchidese, 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.] 
