KEY TO THE GENERA OF MANHATTAN PLANTS. 



32. Carpels 2-valved 84 



33. Carpels beaked Callirrhoe 148 



33. Carpels beakless Mnlva 147 



34. Carpels 5 35 



34. Carpels 12 to 15 Abulilon 146 



35. Involucel none, valves beaked Sida 150 



35. Involucel 3-leaved, valves not beaked Mulvastrum 149 



36. Fruit from a single pistil, separating transversely 



into 1-seeded joints Meibomia 98 



36. Not separating transversely 37 



37. Fruit a legume, 1-celled with 1 parietal placenta. .Leguminosae 41 



37. Fruit not a legume 38 



38. An utricle, 1-celled, 1-seeded, with papery pericarp 39 



38. Not an utricle 40 



39. Utricles imbricated with scarious bracts Amarantaceae 25 



39. No scarious bracts Ciienopodiaceae 24 



40. Fruit large, 1-celled, 1-seeded, with a deeply 4-lobed 



embryo, surrounded by a bony nut-shell and a 



woody or spongy shuck Juglandaceae 15 



40. Not as above 41 



41. Fruit iudehiscent 42 



41. Fruit dehiscent by valves or bursting irregularly 60 



42. Large (6 to 8 cm), many seeded, with a woody peri- 



carp Gucurbita 213 



42. Obpyramidal, angled, closely packed in spherical 

 heads, but not surrounded by an involucre, peri- 

 carp woody, 1-2 celled, 1-2 seeded Sparganium 2 



42. Three-seeded, surrounded by a scant flesh Triosteum 240 



42. Two-celled, 2-seeded, not in heads 43 



42. One-seeded 44 



43. A samara, winged all around (sometimes 1-seeded). Ptelea 



43. Not winged Circaea 173 



44. A samara 45 



44. An acorn Quercus 34 



44. Fruit in dense peduncled heads, capillary bristles at 



base of each, trees Platanus 88 



44. Fruits minute on Ions-bristled stalks, closely aggre- 

 gated in long brown spikes; marsh plants Typha 1 



44. Fruits few in a membranous, reticulated, 5-lobed in- 

 volucre, each 5-ribbed Allionia 55 



44. An akene, several or many in a head surrounded by 



an involucre Compositae 92 



44 Akenes 2, enclosed in an indurated bur-lik« invo- 

 lucre 46 



44. Akenes several from one flower 47 



44. Fruit single in a flower, an akene or 1-seeded nutlet 53 



45. Wing terminal Fraxinus 186 



