1907] HOLM—RUELLIA AND DIANTHERA Bir 
more than one aerial shoot at the same time; some few specimens I 
have found, however, where two flowering stems were developed, 
one of these apical, the other from a bud of a much older portion of 
the rhizome. Two to five roots develop from the internodes or 
directly beneath the buds at the nodes. 
The rhizome of Ruellia is thus relatively short, when it grows in a 
horizontal direction, and its power to wander is very limited. Never- 
theless one may find several specimens with vegetative shoots in 
connection with a single rhizome and at some distance from it; such 
cases are not very rare, but these , 
shoots do not arise from the rhi- 
zome, but from roots, and are thus 
simply root-shoots. The diagram 
of a root-shoot in its first year UL 
(diagram 3) shows two pairs of 
scale-like leaves, one central vege- 
tative shoot (A), one large bud 
(B) behind this, and another one DIAGRAM 3 
(B) to the right, while a smaller 
one (0) is situated in the axil of Z* to the left of A. The position 
of the buds is essentially the same as in the other diagrams, with the 
exception that the aerial shoot (A) occupies here the center of the 
diagram and the apex of the young rhizome, since this is in its first 
year of growth. 
It is readily seen from these diagrams that in young specimens, in 
this case a root-shoot, the aerial stem terminates the rhizome in the 
first year of its growth (diagram 3). In older rhizomes, on the other 
hand, the aerial stem terminates only the apical internode and has 
actually arisen from the axil of a leaf borne upon the basal internode 
of the shoot of the preceding year. The shoot A is thus always 
terminal, and always the mother shoot of C. 
The occurrence of root-shoots has not been recorded for Acan- 
thaceae; at least they are not included in WirrRocx’s extensive list 
of “plants with root-shoots.”’ Three types of such shoots are pro- 
posed by Wirrrocx: reparative, additional, and necessary; those of 
5 Om rotskott hos értartade vixter. Férhdigr. Botan. Sillsk. Stockholm. 1883. 
[Bot. Notiser 1884: 1.] 
