l - CNCFlora

676 Annals of the
Missouri Botanical Garden
son (Bognera). Anubiadeae Engl. (1876) (Anubias more foul-scented and caustic than many other spe-
Schott) and Zantedeschieae are restricted to Africa, cies, and may in part account for less breakage by
while the Spathicarpeae are restricted to southern deterring animals from the plant.
South America.
In some cases DieJ7enbachia may grow in standing
water. In such cases the stems may be rather
MORPHOLOGY OF VEGETATIVE STRUCTURES deeply buried in the mud. Some species, such as
IIABIrF AND GROWTH PATTERNS
D. grayumiana, are frequent in wet habitats, but
most species thrive in well-drained soils. The genus
Dieffenbachia is always terrestrial and caules- is seldom found on road embankments, a habitat
cent (Croat, 1988 [1990]). In terms of growth be- that is very common for species of Anthurium and
havior and habit, Dieffenbachia is not as variable Philodendron. This is perhaps because the two latas
Philodendron, a related genus, but sterile plants ter, principally hemi-epiphytic genera can more
disassociated with notes about habit can be con- easily become estal)lished on the excessively wellfused
with those of Philodendron. Stems of Dieffen- drained and poor clay soils of typical road embachia
are erect, at least on the younger portions, bankments in the Neotropics.
with older portions of the stem typically becoming Development in Dieffenbachia is never heterodecumbent.
This creeping portion of the stem is blastic. Instead, changes in internode size and leaf
sometimes even longer than the erect portion (Fig. size progress without any marked changes in blade
23A). The overall height of any species is usually shape. However, leaf blades of Dieffenbachia that
determined by the thickness, strength, and rigidity ultimately become ( ordate at the base are at first
of the stem. Typically, species such as D. burgeri, simple and acute to obtuse at the base.
D. hammelii, and most plants of D. oerstedii, with
small-diameter stems, do not get to more than 1 m
tall nor do they usually have stems more than 2.5
STEMS
cm in diameter. Alternatively, the taller species like Internodes are ty)ically about as long as broad
D. horichii, D. Ion;,Xisl)atha, and D. standleyi have or even shorter tl(l] broad. Sometimes, as in the
thick stems and reach heights of 2 to 3.5 m. Cul- case of D. galdan7(.siae, petioles are affixed to the
tivated plants growing in a pot and unable to be- stem at an oblique tlngle and the internodes are not
come reclined at the base can grow to indefinite of equal width acloss the diameter of the stem. Inheight.
A plant of D. standleyi cultivated in the stead, one side is as much as 1 cm wider than the
greenhouse of the Missouri Botanical Garden grew other. Most commolllyX internodes are glossy to seup
the side of a wall from a pot to the height of 8 miglossy and smooth though they may be minutely
m.
roughened, appearing with a somewhat weak vel-
The portion of the stem that comes in contact vety sheen, as in tlle case of D. oerstedii. Though
with the ground becomes rooted at the nodes, but for most species tlle internodes remain moderately
stems are rarely buried. Instead, the stems usually glossy even in age, when fresh, the internodes may
creep over the surface of the ground. The growth change promptly. 1 n D. obscurinervia, the stem,
behavior often leads to vegetative reproduction, though initially semiglossy, promptly becomes
since on some species the creeping portion of the etched in a deep, areolate pattern to such an extent
stem tends to produce active branch buds that form that the stem becomes matte and is conspicuously
new growth. Another feature that tends to induce scurfy.
additional branching is the often fragile stem ex- Cataphylls are never present on Dieffenbachia.
tending laterally over the ground, which may be Instead, the new growth on stems of Dieffenbachia
broken by being walked on by animals. Broken is protected by the sheathing petiole of the precedstems
invariably produce new branches. These re- ing leaf.
sults often cause Dieffenbachia to grow in large col- Stem color varies considerably between species
onies, especially in open, better illuminated areas and even within populations of the same species.
of the understory of a forest, along stream banks or Species such as D. Iongispatha, which typically
in open swamps. Examples of colonial growth occur possess stems that are solid green, can sometimes
in D. crebripistillata, D. isthmia, D. killipii, and D. be variegated with paler colors. Typically, stem col-
Oerstedii. Some species, such as the taller D. Ion- or variegation is in the form of streaks rather than
gispatha (to 3.5 m), are usually less colonial. This mottling. The stem may be relatively dark green
is perhaps because it is a species with a large, stout with even darker streaks, in which case the motstem
that is less likely to be broken up by the el- tling would not be too apparent, or, as is more freements.
This species also has a thicker sap that is quently the case, it may be streaked with pale