Index to Vols. 
XXI-XXX. 
Pediastrum Boryanum, cell-structure and 
zoospore formation (*), 30 , 467. 
Pelargonium zonale, pollination and respira- 
tory activity, 21, 491. 
Pellaea, anatomy of xerophilous species (*), 
28 , 671. 
Pellia epiphylla, spermatogenesis (*), 25 , 
436. 
Peloria in Saintpaulia ionantha (*), 26 , 
946. 
Peltaria alliacea, seedling-anatomy, 28 , 717. 
Penaeaceae, embryo (*), 23 , 369; embryo- 
sac, 22 , 329; (*), 23 , 364; endosperm 
(*), 23 , 367 ; ovule (*), 23 , 364. 
Peniston, A. : see Wager, H. 
Peperomia, geophilous species: geographical 
distribution, 21, 158; history, 21, 139; 
inflorescence, 21, 145 ; key to species, 21, 
147; leaves (*), 21 , 143; Mexican and 
Central American species, 21 , 147 ; mor- 
phology (*), 21, 141 ; revision (*), 21, 
139; seedlings (*), 21, 146; systematic 
arrangement, 21, 146. 
— bracteata, description (*), 21, 155. 
— campylotropa, n. sp ., description, 21, 
156. 
— claytonioides, description (*), 21, 154. 
— cyclaminoides, n. sp., description (*), 21, 
149. 
— falsa, description (*), 21, 151. 
— Gaudichaudii, n. sp., description, 21, 154. 
— gracillima, description, 21, 155. 
— macandra, description, 21, 156. 
— minuta, n. sp., description (.*), 21, 150. 
— monticola, description (*), 21, 157. 
— parvifolia, description, 21, 149, 
— peruviana, description, 21, 150. 
— rupiceda, description (*), 21, 157. 
— umbilicata, description, 21, 1 50. 
— verruculosa, n. sp., description, 21, 149. 
Peranema, phyletic consideration, 26 , 306. 
— cyatheoides, external characters (*), 26 , 
247; internal structure (*), 26 , 248; 
prothallus development (*), 30 , 107 ; sorus 
and sporangia (*), 26 , 252 ; development 
(*), 30 , 1 01 , 104. 
Pereskia, spp., seedling-structure (*), 24 , 
126. 
Pericystis, n. gen., description, 26 , 798. 
— alvei, n. sp., a beehive fungus (*), 26 , 
795 , 798 . 
Periderm formation in filicinean petioles, 
24 , 61 1. 
— of fossil Lycopodiales, physiological 
anatomy (*), 27 , 281. 
Perithecium of Polystigma rubrum, develop- 
ment (*), 26 , 761. 
Permeability of cells to the hydrogen ion, 
effect of temperature on (*), 29 , 611. 
— of protoplasm, measured by rate of 
shrinkage of turgid tissues (*), 30 , 283. 
to water, influence of temperature (*), 
30 , 283. 
25 
Permeability, studies in, 29 , 349 ; (*), 29 , 
611 ; (*), 30 , 223. 
Petch, T. : A Preliminary Note on Sclero- 
cystis coremioides, 22, 116. 
— Note on the Biology of the Genus Septo- 
basidium, 25 , 842. 
— The Genus Endocalyx, Berkeley and 
Broome (*), 22, 389. 
Petunia violacea, seedling anatomy, 26 , 737. 
Peuce Lindleii, description (*), 30 , 117. 
Peziza vesiculosa, cytology (*), 22 , 467. 
Phacelia tanacetifolia, seedling-structure, 27 , 
81 r. 
Phellodendron amurense, anatomy of leaf- 
fail, 25 , 97. 
Pherosphaera Fitzgeraldi, anatomy (*), 30 , 
311. 
Philadelphia coronarius, insect visitors, 22, 
621. 
— - grandiflorus, seedling-anatomy, 28 , 724. 
Phloem, general anatomy (*), 22 , 263. 
— of Angiosperms, histology (*), 22 , 245 ; 
of Myristica (*), 22, 526. 
— origin and meaning of medullary phloem 
in stems of Dicotyledons (*), 29 , 567. 
— parenchyma cells (*), 22, 264. 
Phosphorus in Saccharomyces (*), 24 , 70 ; 
role of, 21, 504, 522. 
Photosynthesis, beginning of (*), 24 , 805 ; 
photo-electric theory of, 22, 1 17. 
Phragmidium violaceum, nuclear migrations 
(*), 29 , 293- 
Phyllocactus Hookeri, seedling-structure 
n, 24, 136. 
Phylloglossum, sporeling attached to pro- 
thallus (*), 30 , 605. 
— Drummondii, branching (*), 30 , 328 ; 
morphology (*), 24 , 336; 30 , 316, 318; 
vascular anatomy, 30 , 318. 
Phyllotaxy in Fraxinus excelsior, abnormal, 
29 , 307. 
Phylogeny of Angiosperms (*), 28 , 547 ; of 
Filicales (*), 26 , 269; 28 , 363; 29 , 
495 - 
Physostoma, comparison with Conostoma, 
25 , 35. 
— elegans, abortive seeds (*), 23 , 100 ; 
diagnosis, 23 , 101 ; epidermis (*), 23 , 87 ; 
ground tissue of integument (*), 23 , 89 ; 
integument (*), 23 , 85 ; megaspore mem- 
brane (*), 23 , 100 ; nucellus (*), 23 , 106 ; 
pollen chamber (*), 23 , 90 ; pollen-grains 
(*), 23 , 93 ; pollination (*), 23 , 91 ; pro- 
thallus (*), 23 , 100; secretory sacs (*), 
23 , 97 ; seed organization (*), 23 , 75 ; 
series of transverse sections (*), 23 , 79 ; 
spermatozoids, 23 , 93 ; systematic posi- 
tion's, 108; tapetum (*), 23 , 98 ; varia- 
tion (*), 23 , 83 ; vascular system (*), 23 , 
95 . 
Physostomeae, diagnosis, 25 , 37. 
Phytolacca, spp., seedling-structure, 26 , 187. 
Phytolaccaceae, seedling-structure, 26 , 187. 
