XVI 
FIG. 
1 992. 
994. 
100. 
IOI. 
102. 
List of Illustrations 
PAGE 
Flowers of the Scotch pine (Pinus sylvestris)...+.e100e: 288 
A large (‘‘ macro”) and two small (‘‘ micro”) spores of 
Selaginella martensi (much magnifled)......++.++-.--- 291 
Young carpel, mature carpel, and part of amature cone 
of the silver fir (Adces pectinata) ..- 6. seceeeee eens 297 
Spreading dogbane (Afocynum androsamifolium)....-- 301 
Trap of the spreading dogbane (magnified)............ 305 
Common milk-weed (Asclepias cornutt)..ceeseecceceees 307 
Trop of the milk-weed (magnified)............000-005. 310 
A dogbane flower and its captive........ceeeeeeeeeeee 315 
Nettle and Canada thistle (Urtica dioica and Cnicus 
AP ULISTS onion Seine A LAER PNM CTAE «Wa Maleate yueras 318 
Burdock (Arctttem Lappad) vcecsccnccccccccecneeeecnees 321 
Common wild teasel (Dipsacus sylvestris). ..ccceeceeees 324 
Irish gorse, furze or whin (Ulex EZuropeus).....0..0055 327 
Single blossoms of the nettle........... cess eee eee eoee 331 
Common thistle (Crtcus lamceolatus)..... cece ccceceeee 334 
White clover blossoms gathered in latter summer...... 340 
Pasture thistles (Crzcus pumilis).....0. cece eee eee 343 
Amaranth and sow-thistle (4marantus retroflexus and 
SOMCRUS ASPET)! cig cs ReOaRe AEE. S LEY Ewa aA ROSNER AREAS 348 
“Ribwort”’ (Plantago major) and ‘‘ ripple grass” (Plan- 
LOGO LANCEOLAIG) 2282's coponis some ek eS Vane pemed eae 358 
Cork cells from the leaf scar of the horse-chestnut 
(MUCH MACHINE) 2.0.0 00soGnasding oes caneesaeseyes 367 
Leaf scar of the horse-chestnut (magnified)............ 369 
Witch hazel (Hamamelis Virginica)......cceceevsceveeee 374 
Lengthwise section of a root-tip showing root hairs 
(much magnified)... e023 s.suwaedes dean ad cecsawtag oe 391 
Branches of the alder and of the poplar-leaved birch 
showing numerous lenticels ........... 0. ec ceeeeeeee 393 
