DICOTYLEDONS. 
^33 
Order lo. Gynandrae. The entire flower zygomorphic in origin and de- 
velopment; by the torsion of the long inferior ovary (i) the anterior side of the 
mature flower usually becomes posterior; both of the trimerous perianth-whorls 
petaloid, the posterior leaf of the inner one (the labellum) generally provided 
with a spur ; of the six typical stamens of the two whorls only the anterior ones 
are eventually developed, and in (i) (with the exception of Cypripedium) the 
anterior one of the outer whorl is alone fertile and has large anthers, the two 
anterior ones of the inner whorl forming small staminodes ; but in Cypripedium it 
is these latter that are fertile, the anterior one of the outer whorl forming a large 
staminode; in (2) the same occurs, or the three anterior ones are fertile ; filaments 
of the fertile and sterile stamens coherent with the three styles into a gynostemium ; 
pollen in single grains, tetrads, masses, or pollinia ; ovary inferior and unilocular 
with parietal placentation (i) or trilocular with axile placentation (2) ; ovules 
anatropous; seeds very numerous, very small, without endosperm, and with the 
embryo undiff"erentiated. Small herbs or larger shrubby plants ; the tropical 
Orchideae often epiphytal and furnished with peculiar aerial roots ; our native 
species perennial with underground rhizomes or tubers ; some Orchideae are 
saprophytes destitute of chlorophyll, and a few have even no roots {Epipogium^ 
Coral lor hi%a). 
Families: i. Orchideae. 
2. Apostasiaceae. 
The BurmanniacesB with cymose inflorescence, three or six fertile epipetalous 
stamens, free tripartite style, and uni- or tri-locular inferior ovary, are allied to the 
Gynandrae by their small seeds without endosperm and their undifferentiated 
embryo ; and in this order, which consists for the most part of small plants, there 
are some saprophytes destitute of chlorophyll. 
CLASS XIL 
DICOTYLEDONS, 
The ripe Seed of Dicotyledons contains either a large endosperm and a small 
embryo (as in Euphorbiaceae, Coffea, Myristica^ Umbelliferae, Ampelideas, Polygon- 
aceae, Csesalpineae, &c.) ; or the embryo is comparatively large, and the endosperm 
occupies but a small space {e.g. Plumbagineae, Labiatae, Asclepiadeae, &c.) ; or, 
thirdly, the endosperm is entirely wanting, and the embryo fills up the whole of the 
space enclosed by the testa, and thus, when ripe, often attains a very considerable 
size {e.g. ^scuius, Juglans, Cucurbita, Tropceolum^ Cupuliferae, Leguminosae, &c.); 
though in small seeds it still remains of moderate dimensions (as in Cruciferae, Com- 
positae, Rosiflorae, <fec.). The absence of endosperm generally results from its 
absorption by the rapid growth of the embryo before the ripening of the seed ; 
only in a very few cases is it rudimentary from the first {TropcBolum^ Trapa). In 
most of the Nymphaeaceae and in the Piperaceae the embryo and the endosperm 
which surrounds it both remain small, the rest of the space within the testa being 
occupied by perisperm. 
