NATURAL ORDERS. lxXlX 



LXV. Elaaagnaceae. Shrubs or trees, with scurfy leaves. Flowers 

 mostly unisexual. Ovary free in the bottom of the perianth-tube, with 

 1 erect ovule. 



LXVI. Santalaceae. Perianth-lobes valvate. Ovary inferior, 1-celled, 

 with 2 or 4 pendulous ovules. Spike simple. 



LXVII. Aristolochiaceae. Perianth irregular, or 3-lobed. Stamens 

 6 or 12. Ovary inferior, 3- or 6-celled, with numerous ovules. 



LXVIII. Euphorbiaceae. Flower unisexual. Fruit separating into 

 3 (rarely 2 or more) carpels, leaving a persistent axis, each carpel con- 

 aining 1 or 2 pendulous seeds. 



LXIX. Empetraceae. Differs from Euphorbiacese in the ovules and 

 seeds erect. 



LXX. Ceratophyllum and Callitriche. Anomalous aquatic genera. 

 Perianth none. Ovary with 1 or 4 cells, and 1 seed in each. 



LXXI. Utricacese. Flowers unisexual, small and green. Stamens 

 opposite the perianth-divisions (usually 4). Ovary free, with a single 

 ovule, and 2 (rarely 1) styles or stigmas. 



LXXII. Ulmaceaa. Trees. Flowers often bisexual, the stamens 

 opposite the lobes. Ovary free, 2-celled, with 1 erect ovule in each cell. 



LXXIII. Amentaceas. Trees or shrubs. Flowers unisexual, the males 

 in catkins with an imperfect perianth, or none at all. Fruit of the 

 females 1-celled. 



LXXIV. Coniferas. Trees or shrubs with stiff or scale-like leaves. 

 Flowers unisexual, the males in catkins without perianth. Ovules and 

 seeds in the females not enclosed in any ovary or pericarp. 



CLASS II.— MONOCOTYLEDONS. 



In germination the plumule is developed from a sheath-like cavity 

 on one side of the embryo. [The vascular tissue of the stem occurs 

 in scattered bundles amongst the cellular. The nerves of the leaves 

 are more or less parallel (except in Aroideaa, Dioscorideaa, Paris, and in 

 some Liliaceas). The parts of the flower are usually in twos or threes.] 



* Perianth none, or of 4 small sepals or bracts. 



LXXV. Typhaceae. Flowers unisexual, intermixed with bracts in 

 dense heads or spikes. Fruit a dry nut. 



LXXVI. Aroideas. Flowers unisexual, often intermixed with bracts, 

 in dense heads or spikes, mostly in a spatha. Fruits usually succulent. 



LXXVII. Lemnacese. No distinct stem. Flowers (very scarce) on 

 the edge of the small leaf-like floating fronds. 



LXXVIII. Naiadeaa. Floating or submerged plants. Flowers distinct 

 or in loose spikes. Stamens 1, 2, or 4. Ovaries 1, 2, or 4. 



** Perianth wholly or partially petal-like. Ovary apocarpous, 

 LXXIX. Alismacese ; the only British family of the group. 



*** Perianth wholly or partially petal-like. Ovary inferior. 

 LXXX. Hydrocharideas. Floating or submerged plants. Flowers 

 usually unisexual. Perianth regular, with a slender tube. 



LXXXI. Orchidaceae. Perianth very irregular. Anther 2-celled, 

 combined with the style in an axile column. 



LXXXII. Irideae. Like the Amaryllis family, but stamens 3 Leaves 

 often in two opposite rows, 



