1923] Index 233 
Potamogeton bupleuroides, 185; 
crispus, 206; foliosus, 108; Friesii, 
206; heterophyllus, var. gramini- 
folius, 6; pulcher, 48; Robbinsii, 
107; strictifolius, 206; Vaseyi, 
206. 
Potentilla emarginata, 113; fragi- 
formis, 113; monspeliensis, 9; 
pacifica, 9; palustris, 9; triden- 
tata, 9. 
Preissia quadrata, 193. 
Prickly Ash, 175. 
Primula farinosa, 10, var. macro- 
poda, 10. 
Primulaceae, 10. 
Prunella, 40; vulgaris, 40, forma 
albiflora, 40, var. lanceolata, 41, 
forma candida, 41, forma iodo- 
calyx, 41. 
Prunus cuneata, 69, 71-73; de- 
pressa, 69-71, 73; Padus, 169-171, 
177, in America, Naturalized 
Occurrence of, 169; pennsyl- 
vanica, 9; pumila, 69-73, 211, 
var. cuneata, 73; serotina, 170, 
171; susquehanae, 69, 71-73; vir- 
giniana, 169-171. 
Pseudotaenidia montana, 168. 
Ptilidiaceae, 196. 
Ptilidium ciliare, 196; pulcherri- 
mum, 196. 
Puccinellia distans, 208, var. tenuis, 
208. 
Purple Gerardia, 62. 
Pyenanthemum, 41; clinopodioides, 
41; flexuosum, 41; incanum, 41; 
muticum, 41; verticillatum, 41: 
virginianum, "41. 
Pyrethrum, 16. 
Pyrola chlorantha, 10; grandi- 
flora, 114; minor, 10; secunda, 
var. obtusata, 10. 
Pyrus dumosa, 9. 
Quercus, 164, 165; arkansana, 180; 
caput- -rivuli, 179; coccinea, 184; 
megacarpa, 180. 
Radula complanata, 197; obconica, 
197; tenax, 197. 
Radulaceae, 197. 
Ranunculaceae, 8. 
Ranunculus acris, 8; Cymbalaria, 
107; hyperboreus, 8; lapponicus, 
8; pedatifidus, var. leiocarpus, 
113; pennsylvanicus, 8; pyg- 
maeus, 113; reptans, 8. 
Reboulia hemisphaerica, 193. 
Rebouliaceae, 193. 
Red Ash, 176; Currant, 176. 
Redbud, 204. 
Reports on the Flora of the Boston 
District, —X XXVIII. 25, XX- 
Aim, OF AG. 00, XLI. 185. 
Revision of the American Species 
of Hypoxis, 120, 151. 
Rhinanthus, 65; Crista-galli, 11, 65, 
var. fallax, 65. 
Rhododendron lapponicum, 114; 
nudiflorum, 116. 
Rhode Island, Habenaria hyper- 
borea in, 44. 
Ribes prostratum, 9. 
Riccardia latifrons, 193, 198, multi- 
fida, 193, 198; palmata, 193; 
pinguis, 193; sinuata, 193. 
Riccardiaceae, 193. 
Riccia, 74, 199; arvensis, 98, 193; 
Austini, 193; Beyrichiana, 193; 
crystallina, 74, 193; dictyospora, 
193; fluitans, 74, 193; Frostii, 
193, 198; hirta, 193; membrana- 
cea, 74, 193; sorocarpa, 193; 
Sullivantii, 74, 193. 
Ricciaceae, 193. 
Ricciella, 74; crystallina, 199; flui- 
tans, 199; membranacea, 199; 
Sullivantii, 199. 
Ricciocarpus natans, 193. 
Robbins, C. A., Cladonia Beau- 
montii in Massachusetts, 46. 
Robinia, 180; Boyntonii, 183; fer- 
tilis, 182; grandiflora, 180-182; 
hispida, 180, 183; longiloba, 183; 
pallida, 182; pedunculata, 183; 
speciosa, 181, 182; unakae, 180. 
Robinson, B. L., Emily Frances 
Fletcher, 149. 
Rosaceae, 9. 
Rubiaceae, 11. 
Rubus arcuans, 147; Chamaemorus, 
9, 99; elegantulus, 211; frondosus, 
211; 'glandicaulis, 210; hispidus, 
var. major, 211; ; idaeus, 9; jacens, 
211; multispinus, 147; orarius, 
147; pergratus, 211; recurvans, 
211; triflorus, 9; vermontanus, 
211. 
Rumex acetosella, 8; occidentalis, 8. 
Ruppia, 107. 
Rynchospora inundata, 48. 
Sabatia stellaris, 48. 
Sagittaria graminea, 185. 
