ern."

Ostrich-fern, 104-109.
germination of spores, 104.
prothallium, 104, 105.
archegonium, 105, 106.
antheridium and spermatozoids, 106.
fertilization, 107.
embryo and young plant, 107, 108.
comparison with sporogonium of bryophytes, 109.

Ovary, 129, 148, 156, 202.

Ovule, 129, 131, 144, 148, 151, 179.

_Oxalis_. See "Wood-sorrel."

_Oxydendrum_, 211; Fig. 116.

Oxygen, 2, 95.

Palea, 161.

Palisade parenchyma, 178.

Palm, 157.
date, 159.
coco, 159.

_Palmae_. See "Palm."

Palmate, 171.

Palmetto, 159.

_Pandaneae_, 159.

_Papaveraceae_. See "Poppy."

Papaw, 186; Fig. 100.

_Papilionaceae_, 208.

Pappus, 223.

_Papyrus_, 161.

Paranucleus, 231.

Parasite, 54.

Parenchyma. See "Soft tissue."

_Parmelia_, 73, 75; Fig. 44.

Partridge-berry, 223, 228.

_Passiflora_. See "Passion-flower."

_Passiflorinae_, 205.

Passion-flower, 204; Fig. 112.

Pea, 207, 208; Fig. 115.

Peach, 206.

Pear, 206.

_Pediastrum_, 23; Fig. 11.

_Pelargonium_, 197.

Peltate, 190.

_Peltigera_, 75; Fig. 45.

_Penicillium_, 71; Fig. 42.

Pepper, 183.

Perianth. See "Perigone."

Periblem, 176.

Perigone, 143, 148, 151, 170.

Perisperm, 163.

_Perisporiaceae_, 66.

Periwinkle, 219.

_Peronospora_, 60; Fig. 35.

_Peronosporeae_, 57.

Persimmon, 212; Fig. 117.

Petal, 148, 174, 179.

Petiole, 173.

Petunia, 215; Fig. 119.

_Peziza_, 73; Fig. 43.

_Phacelia_, 214.

_Phaeophyceae_. See "Brown algae."

Phaenogam. See "Spermaphyte."

_Phascum_, _-aceae_, 99, 101; Fig. 65.

_Philadelphus_. See "Syringa."

Phloem, 110, 124, 135, 137, 150, 173, 176.

_Phlox_, 214; Fig. 118.

_Phoenix dactylifera_. See "Date-palm."

Phosphorus, 2.

_Phragmidium_, 81; Fig. 47.

_Physarum_, 14.

_Physianthus_, 220.

Physiology, 3.

_Phytolacca_, _-aceae_. See "Poke-weed."

_Phytophthora_, 60.

Pickerel-weed, 156, 228; Fig. 84.

Picric acid, 156, 233.

Pig-weed. See "Amaranth."

Pine, 9, 10, 129, 142.

Pineapple, 156.

Pine-sap, 210; Fig. 116.

_Pinguicula_, 218.

Pink, 181, 185; Fig. 97.

Pink-root, 218; Fig. 122.

Pinnate (leaf), 159.
veined, 171.

_Pinnularia_, 42; Fig. 24.

_Pinus sylvestris_. See "Scotch pine."

_Piper_. See "Pepper."

_Piperineae_, 183.

Pistil, 143, 145, 174.

Pitcher-plant, 194, 195; Fig. 105.

Pith, 130, 174, 177.

Placenta, 148, 179.

Plane, 183.

_Plantago_, _-ineae_. See "Plantain."

Planta