DICOTYLEDONS 301 
spiral arrangement), and study a flower with its tri- or bi- 
stigmatic pistil, three stamens and (usually) six perianth bris- 
tles. Cyperus differs mainly in its two-ranked spikelets, and 
absence of perianth bristles. 
(j) Study an Amaryllis flower in longitudinal and cross- 
sections as in the lily (c). The small, somewhat zygomorphic 
flowers of the banana (Musa) may be substituted for the amar- 
yllis. Note the absence of one stamen. Study also the ma- 
ture fruit (usually seedless) in sections. 
(k) Make a similar study of the Iris flower. 
(lt) For Orchids the Lady’s Slipper (Cypripedium) should be 
studied, and its two stamens grown fast to the tristigmatic 
style, one petal slipper-shaped (“lip”), the other two much 
like the pointed, rather elongated sepals (two of which are often 
united). Note the sticky pollen, and the very numerous, mi- 
nute seeds. For this may be substituted the native Orchis, or 
Ibidium, or various greenhouse orchids; here the single stamen 
is attached to the bistigmatic style, and the petals and sepals 
are very variable, one petal (“‘lip’”’) being always much longer 
and more showy. 
CLASS DICOTYLEDONEAE. 
Tue DIcoTyLEDONS 
547. Cotyledons two; leaves opposite on the stem, 
later ones opposite or alternate; vascular bundles in 
the stem arranged cylindrically (in a ring 
as seen in cross-section) ; vascular bundles 19) 7, 
in the leaf-blades irregularly netted mie B 
(“‘netted-veined”’); perianth whorls gy 
mostly quinate (in 5’s). 
548. There are two greater types (sub- “Fa ea ih 
classes) of Dicotyledons, which are dis- “~~ 
tinguished by the structure of the flower axis, as follows: 
1. Flower axis cylindrical, spherieal, hemispherical or flat- 
tened, bearing on its surface the flower parts (perianth, stamens 
and carpels)..... “ Axis Flowers”’ (AXIFLORAE). 
2. Flower axis more or less expanded into a disk or cup, 
