﻿INDEX. 



295 



Stamens : 



Emplacement of, 230. 244 



Evolution from asexual sporophytes, 241. 245 

 Staminate disk : 



General description of, 149-160 



In Cycadocephalus, 167 



In Welwitschia, 229 



List of forms, 167 



Significance in angiosperm evolution, 246 

 Staminate frond, 151-155 ct scq. 



Homology of, 229 

 Stangcria, 31, 82, 189, 197, 201, 203, 209, 220, 225. 

 227, 233 



Leaf-base bundle pattern, 62, 63 



Nervation of, 213, 239 



Xylem of, 198 

 Stangcria faradoxa, *29, 142, 223 



Fronds of, *2ii 



Megaspore bundle of, *22i 



Peduncular bundle of, *222 



Seedling of, *209 



Sporangial wall of, 159 



Thickets of. in Natal, 189 

 State University of Iowa : 



Cycad collection of, 7 



Cycad material from, 144 

 Stephanospermum, pollen of, *i5o 



Seed of, 218 

 Struthiopteris, 239 



germanica, 241 

 Sundance, Wyoming, strobilus from, 143 

 Swiss lake-dwellers, use of Sambucus drills by. 48 

 Tree ferns : 



Branching of. 36 



Similarity to Cycads in size of. 35 

 Trigonocarpon, 218, 246 

 Trunk forms, 26, 29, 57 



Obliquely compressed, 27 



Vertically shortened, 27 



Transversely elliptical, 28, 29 

 Trunk numbers, 53 

 Trunk structure, 227, 228 



Of Cycadacca, 195-208, 213 



Of Cycadcoidca, 51-80 

 Tumhoa, *229, 230 

 Types (see Cycad collections) 

 Unexplored or little-known regions, 18 

 Wealden sandstones, cycads from, 14 

 Welwitschia mirabilis, 229 



Staminate disk of, 245 

 Williamsonia, 13, 16, 81, 82, 91, 102, 129, 137. 742. 



156, 166, 174, 227 

 Williamsonia Blanfordi, *i~ 



Williamsonia gigas. 16, 17. 38, 81. *I52, *I53, 

 *iS4. 174 



Bisporangiate strobilus of, 167 



Fruit-bearing branch of, 38 



Habitus, S3 



Restoration of, 18 

 Williamsonia Lcckcnbyi, 17 

 Morierci, 107 

 becten, 17, 117 

 Wyoming, cycad localities of central. 10 



Of Inyan Kara Mountain, 8 



Xylem zone of Cycadcoidca, 74-77 

 Yale Museum : 



Cycad collections in, 8, 10 



Matching of isolated cycad trunk fragments 

 in. 39 

 Yorkshire coast, cyc.-d specimens from, in Paris 



Museum, 13. 82 

 Young fruits, 147-149, 169-186 

 Yuccitcs, 81 

 Zainia, 189, 191-195, 199, 207, 220, 225, 226, 227. -'32 



Fertilization in. 216 



Microsporophylls of, 215 



Monoxylic vascular zone of, 197 



Old peduncle bundles in pith of. 196 



Prefoliation of. 87, 209, 210 



Sporophyll homologies of, 232 



Trunk habitus of. 31, *igi 

 Zainia floridana. 101, 154, 162. 191, *I93. *I94, *I95 



Branching of, 194 



Cones of, *I94 



Cortical bundles of. *20l 



Foliar reversion in cone of, 214 



General features of, 192-195 



Leaf-base bundle pattern of, *62 



Micropylar tube diameter, 218 



Prefoliation, *85 



Range of, 192 



Spiral cells of xylem. 75 



Tap-root of, 197, 207, 208 



Xylem of, 198 

 Zainia furfuracca, 93. 191, 212 

 Zainia gigas. 81, 82, *I54 



Described by Williamson. 15 

 Zainia Lindeni, *8$ 

 Zainia ''glabra," *I92 



Pinnules of, *2I2 

 Zainia integrifolia, 191 



Megasporophyll of, *2i7 



Microsporophylls of, *2i4 



Seed-bundle system of. *2ig 

 Zainia niuricata, 201 



Phyllotaxy of cones, 215 



Seed-bundle system of, *2I9 

 Zainia Poppigiana, 190 



pseudoparasitica, 190. 212 

 pumila, range of. 192 

 pygni(ca, 191. 21 1 

 Cones of, 214 

 Zainia Roczlii, *igi 



Leaf base of, *62 

 Zainia van Houttei, *igo 

 Zainia "vernicosa," *40 



Pinnules of, *2I2 

 Zainia "Vroomi" *I03 



Zainia Wallisii, True petiolar spines of, 212 

 Zainia-. 34, 44. 63. 236, 237 



Ovulate cone homologies of, 235 



Trunk structure, 34 



Low stature of, 35 

 Zamiostrobus stenorachis, *232 

 Zamitcs, fronds of, 82 

 Zamitcs gigas. 81 



Zurich, limestone cores cut by lake-dwellers in 

 museum at. 48 



