16-385 bryum1-t.jpg bryum1-v.jpg 72 bryum1-h.jpg 163 Bryum species with prostrate moss gametophyte and maturing sporophytic capsules. The capsules are complex, dominating the body of the sporophyte. Bryophyta, Bryales, gametophyte, sporophyte, moss 0.1
16-386 bryum2-t.jpg bryum2-v.jpg 59 bryum2-h.jpg 147 Bryum capsules form the sporophyte. The moss gametophyte is prostrate and individual plants are inconspicuous. Bryophyta, Bryales, gametophyte, sporophyte, moss 0.2
16-386 polytrichum-t.jpg polytrichum-v.jpg 91 polytrichum-h.jpg 209 Polytrichum species with emergent erect gametophyte. The sporophyte of this plant hydroids and leptoids -- moss analogs of xylem and phloem. Bryophyta, Bryales, gametophyte, moss 0.3
16-095 16-095t.jpg 16-095v.jpg 106 16-095h.jpg 533 Mnium antheridiaphore with protective leaves and rhizoids. This moss contains elongated slender antheridia that are largely exposed on the elevated antheridophore. Bryophyta, Bryales, antheridia 1
16-094 16-094t.jpg 16-094v.jpg 249 16-094h.jpg 545 Mnium developing antheridia. The antheridia are at a diversity of different developmental stages on the antheridiophore from early spermatogenesis to sperm cell maturation. Bryophyta, Bryales, antheridia 2
16-104 16-104t.jpg 16-104v.jpg 132 16-104h.jpg 538 Mnium archegoniophore provides protective leaves and rhizoids amid the developing archegonia of this moss. Archegonia range from maturity (see egg cell on the left), to quite imature stages. Bryophyta, Bryales, archegonia 3
16-103 16-103t.jpg 16-103v.jpg 129 16-103h.jpg 715 Mnium archegonium. Archegonia are highly elongated, with thick necks and elongated axial rows of numerous neck cells. This reflects a more primitive form of gametangia. Bryophyta, Bryales, archegonia 4
16-386 mnium-eggs-t.jpg mnium-eggs-v.jpg 79 mnium-eggs-h.jpg 220 Mnium archegonia. Two archegonia are evident here. The axial row, having begun degeneration, reflects a receptive egg. Note ventral canal cell in the right archegonium. Bryophyta, Bryales, archegonia, gametophyte, moss 4.01
16-386 mnium-egg-redo-t.jpg mnium-egg-redo-v.jpg 82 mnium-egg-redo-h.jpg 228 Mnium archegonium containing a receptive egg cell as viewed using differential interference contrast microscopy. Bryophyta, Bryales, archegonia, gametophyte, moss 4.02
16-386 mnium-egg-t.jpg mnium-egg-v.jpg 82 mnium-egg-h.jpg 228 Mnium archegonium containing a receptive egg cell. Bryophyta, Bryales, archegonia, gametophyte, moss 4.03
16-386 moss-liverwort-t.jpg moss-liverwort-v.jpg 169 moss-liverwort-h.jpg 417 Mnium archegonium containing a receptive egg cell. Bryophyta, Bryales, Marchantiales, gametophyte, moss, thallose liverwort 4.1
16-386 marchantia-gametophore-lawn-t.jpg marchantia-gametophore-lawn-v.jpg 140 marchantia-gametophore-lawn-h.jpg 313 Marchantia thallus with archegoniophores (lobed umbrellas) and antheridiophores (webbed umbrellas). Bryophyta, Bryales, Marchantiales, gametophyte, archegoniophore, antheridiophore, thallose liverwort 4.2
16-386 reboulia-t.jpg reboulia-v.jpg 47 reboulia-h.jpg 131 Reboulia archegoniophores appear largely similar to those of Marchantia. Bryophyta, Bryales, Marchantiales, gametophyte, archegoniophore, thallose liverwort 4.21
16-386 marchantia-gametophores-t.jpg marchantia-gametophores-v.jpg 81 marchantia-gametophores-h.jpg 193 Marchantia thallus with archegoniophores (lobed umbrellas) and antheridiophores (webbed umbrellas). Bryophyta, Bryales, Marchantiales, gametophyte, archegoniophore, antheridiophore, thallose liverwort 4.3
16-386 marchantia-gemma-t.jpg marchantia-gemma-v.jpg 56 marchantia-gemma-h.jpg 143 Marchantia thallus with gemma cups, contining the vegetative propagules called gemmae. Bryophyta, Bryales, Marchantiales, gametophyte, archegoniophore, antheridiophore, thallose liverwort 4.4
16-102 16-102t.jpg 16-102v.jpg 241 16-102h.jpg 642 Marchantia archegoniophore. Archegonia at a range of developmental stages are evident on the underside of the archegoniophore. Bryophyta, Marchantiales, archegoniophore 5
16-093 16-093t.jpg 16-093v.jpg 208 16-093h.jpg 410 Marchantia mature antheridium. The sperm cells form in developmental merophytes (derivatives of the same cell lineage). The antheridia are retained within the antheridiophore. Bryophyta, Marchantiales, antheridia 5.5
16-101 16-101t.jpg 16-101v.jpg 136 16-101h.jpg 608 Marchantia archegoniophore. Immature archegonia through fertilized archegonia are evident on the underside of the archegoniophore. Bryophyta, Marchantiales, archegoniophore 6
16-100 16-100t.jpg 16-100v.jpg 102 16-100h.jpg 439 Marchantia developing archegonia. A gradation of archegonial stages are evident on teh underside of this archegoniophore. Note immature ventral canal cell and neck canal mother cell (right). Bryophyta, Marchantiales, archegonia 7
16-098 16-098t.jpg 16-098v.jpg 175 16-098h.jpg 2179 Marchantia archegonial stages. Note the archegonial initial to the left, 2-4 cell stage, to a fertilized archegonium on the right. Of what advantage would this strategy be? Bryophyta, Marchantiales, archegonia 8
16-099 16-099t.jpg 16-099v.jpg 220 16-099h.jpg 442 Marchantia mature archegonium. Note the large egg cell, ventral canal cell, neck canal cells and axial row. Prior to fertilization, the cells intervening between the cap cell and egg break down. Bryophyta, Marchantiales, archegonia 9
16-097 16-097t.jpg 16-097v.jpg 87 16-097h.jpg 331 Marchantia archegonial stages. Note archegonial row initial (left). The central archegonium appears ready for fertilization. Bryophyta, Marchantiales, archegonia 10
16-092 16-092t.jpg 16-092v.jpg 222 16-092h.jpg 442 Marchantia young sporophyte. This archegonium has been recently fertilized and is at about the 64 celled stage. The polarity of the sporophyte is poorly distinguished. Bryophyta, Marchantiales, archegonia 11
16-096 16-096t.jpg 16-096v.jpg 285 16-096h.jpg 845 Marchantia mature archegonium. Note the large egg cell, ventral canal cell, and obliquely sectioned neck canal cells. A rhizoid is provides some protection. (Nomarski interference contrast microscopy) Bryophyta, Marchantiales, archegonium 11
16-091 16-091t.jpg 16-091v.jpg 257 16-091h.jpg 485 Marchantia young sporophyte. This sporophyte is still located within the archegonium. Note the degerate material in the archegonial neck through which the sperm entered. Bryophyta, Marchantiales, sporophyte 12
16-090 16-090t.jpg 16-090v.jpg 133 16-090h.jpg 484 Marchantia young sporophyte. The foot, seta and developing capsule differentiate early in this differentiating sporophyte. Bryophyta, Marchantiales, sporophyte 13
16-089 16-089t.jpg 16-089v.jpg 111 16-089h.jpg 403 Marchantia young sporophyte. The foot, seta and developing capsule are evident in this differentiating sporophyte. Bryophyta, Marchantiales, sporophyte 14
16-088 16-088t.jpg 16-088v.jpg 163 16-088h.jpg 558 Marchantia maturing sporophyte. Spores are aligned parallel to elators within the capsule, shown here prior to their separation. Bryophyta, Marchantiales, sporophyte 15
16-087 16-087t.jpg 16-087v.jpg 103 16-087h.jpg 474 Marchantia mature sporophyte. The capsule is filled with spores and elators that aid dissemination. These hang, pendulous from the archegoniophore. Bryophyta, Marchantiales, sporophyte 16
16-081 16-081t.jpg 16-081v.jpg 213 16-081h.jpg 435 Psilophyton princeps, a Trimerophyte. Plants in this group are believed to be the source of most vascular land plants. Museum, Devonian, Trimerophyta 80
16-082 16-082t.jpg 16-082v.jpg 67 16-082h.jpg 411 Zosterophyllophyte in the Devonian. Strobili consist of reniform sporangia on short laterals, and increasing vegetative complexity. Museum, Devonian, Zosterophyllophyta 16.4
16-083 16-083t.jpg 16-083v.jpg 89 16-083h.jpg 441 Cooksonia and Rhynia in a diorama of life 400 mya. Milwaukee Public Museum. Museum, Devonian, Rhyniophyta 81
16-084 16-084t.jpg 16-084v.jpg 109 16-084h.jpg 472 Reconstruction of a Devonian scene. A diorama by the Milwaukee Public Museum. Museum, Devonian 16.2
16-085 16-085t.jpg 16-085v.jpg 81 16-085h.jpg 631 Kidstone and Gwynne-Vaughn examining the fossils of the Rhynie chert, where Rhynia and many of the Rhyniophytes were discovered. Early Fossil Hunters 16.1
16-086 16-086t.jpg 16-086v.jpg 68 16-086h.jpg 271 Origin of Alternation of Generations is depicted in these two diagrams illustrating the isomorphic (homologous) and transformation (antithetic) models. Alternation of Generations 16.6
16-059 16-059t.jpg 16-059v.jpg 109 16-059h.jpg 2109 Lycopodium sporangial initials are characteristic of the eusporangiate development. Note the axial origin of the sporangium. Lycophyta, Lycopodiales, sporangial ontogeny 17
16-069 16-069t.jpg 16-069v.jpg 195 16-069h.jpg 580 Lycopodium obscurum plectostele. Lycophyta, Lycopodiales, vegetative, sporophyte 17.01
16-070 16-070t.jpg 16-070v.jpg 107 16-070h.jpg 343 Lycopodium adpressum apical meristem with apical cell. Lycophyta, Lycopodiales, vegetative, sporophyte 17.01
16-071 16-071t.jpg 16-071v.jpg 193 16-071h.jpg 353 Lycopodium obscurum shows two microphyll morphologies, overtopped strobili. Vilas County, Wisconsin. Lycophyta, Lycopodiales, vegetative, sporophyte 17.01
16-072 16-072t.jpg 16-072v.jpg 166 16-072h.jpg 341 Lycopodium inundatum rhizome with conspicuous leaf traces, exarch maturation. Lycophyta, Lycopodiales, vegetative, sporophyte 17.01
16-073 16-073t.jpg 16-073v.jpg 88 16-073h.jpg 293 Lycopodium clavatum shows three microphyll morphologies, multiple strobili and relatively great specialization. Vilas County, Wisconsin. Lycophyta, Lycopodiales, vegetative, sporophyte 17.01
16-074 16-074t.jpg 16-074v.jpg 178 16-074h.jpg 558 Lycopodium clavatum rhizome cross section showing an impressive plectostele, leaf traces and sclerified cortical sheath. Lycophyta, Lycopodiales, vegetative, sporophyte 17.01
16-075 16-075t.jpg 16-075v.jpg 163 16-075h.jpg 281 Lycopodium annotinum shows two microphyll morphologies, terminal strobili and determinate growth. Vilas County, Wisconsin. Lycophyta, Lycopodiales, vegetative, sporophyte 17.01
16-076 16-076t.jpg 16-076v.jpg 102 16-076h.jpg 184 Lycopodium lucidulum showing interrupted strobilus, sporophylls nearly identical to microphylls. A propagule known as a bulbil is also visible. Lycophyta, Lycopodiales, vegetative, sporophyte 17.01
16-077 16-077t.jpg 16-077v.jpg 196 16-077h.jpg 337 Lycopodium squarrosum showing epiphytic, tropical habit. Photo taken at Australian National Botanical Garden, Canberra. Lycophyta, Lycopodiales, vegetative, sporophyte 17.01
16-078 16-078t.jpg 16-078v.jpg 241 16-078h.jpg 442 Lycopodium sp. in Costa Rica, shows typical habit of an epiphytic lycopod. Lycophyta, Lycopodiales, vegetative, sporophyte 17.01
16-079 16-079t.jpg 16-079v.jpg 148 16-079h.jpg 272 Lycopodium phlegmaria showing epiphytic, tropical habit. Photo taken at Australian National Botanical Garden, Canberra. Lycophyta, Lycopodiales, vegetative, sporophyte 17.01
16-080 16-080t.jpg 16-080v.jpg 110 16-080h.jpg 357 Lycopodium lucidulum shows indeterminate growth on all axes. Interrupted reproductive regions constitute poorly defined strobilar regions. Lycophyta, Lycopodiales, vegetative, sporophyte 17.01
16-061 16-061t.jpg 16-061v.jpg 125 16-061h.jpg 410 Lycopodium lucidulum bulbil viewed in longitudinal section, showing subtending leaf, as well as shoot and root apices. Lycophyta, Lycopodiales, vegetative, sporophyte 17.02
16-058 16-058t.jpg 16-058v.jpg 111 16-058h.jpg 1830 Lycopodium sporangial development. This eusporangium is still reasonably early in development. Note the origin of layering in the sporangium -- an early stage in formation of the sporangial wall. Lycophyta, Lycopodiales, sporangial ontogeny 18
16-057 16-057t.jpg 16-057v.jpg 213 16-057h.jpg 1664 Lycopodium later sporangial development. Sporogenous tissue is just beginning to become conspicuous by its greater cytoplasmic density and accumulation of dense nuclei. Lycophyta, Lycopodiales, sporogenesis 19
16-056 16-056t.jpg 16-056v.jpg 177 16-056h.jpg 1144 Lycopodium late sporangial development. Sporogenous tissue is quite well defined at this stage. The thick walls surrounding developing sporocytes is characteristic. Lycophyta, Lycopodiales, sporogenesis 20
16-055 16-055t.jpg 16-055v.jpg 102 16-055h.jpg 1667 Lycopodium clavatum sporogenesis I. Sporocytes have just undergone meiosis and spores are present in tetrads in this image. Note the thickness of the sporangial wall and the organization of tapetal cells. Lycophyta, Lycopodiales, sporogenesis 21
16-054 16-054t.jpg 16-054v.jpg 84 16-054h.jpg 1506 Lycopodium clavatum sporogenesis II. Post-meiotic spores remain in tetrads in this image. Tapetal cells are found among the sporocytes at this stage. Lycophyta, Lycopodiales, sporogenesis 22
16-053 16-053t.jpg 16-053v.jpg 102 16-053h.jpg 1587 Lycopodium clavatum sporogenesis III. Tetrads have broken down, releasting the spores as individual cells. Exine walls are well developed in the spores at this stage. Tapetal cells found among the sporocytes are beginning to break down. Lycophyta, Lycopodiales, sporogenesis 23
16-052 16-052t.jpg 16-052v.jpg 116 16-052h.jpg 1968 Lycopodium clavatum sporogenesis IV. Spores with conspicuous exines separate. Occasionally cells with their trilete mark evident are visible. Tapetal cells found among the sporocytes continue to break down. Lycophyta, Lycopodiales, sporogenesis 24
16-051 16-051t.jpg 16-051v.jpg 116 16-051h.jpg 1534 Lycopodium mature eusporangium. Spores continue to increase in density as they accumulate food stores. The tapetum breaks down as its nutrients dry up in preparation for dehiscence. Note the laminar location of sporangial attachment on the sporophyll. This is characteristic of some of the more derived of the Lycopodiaceae. Lycophyta, Lycopodiales, sporangium 25
16-050 16-050t.jpg 16-050v.jpg 258 16-050h.jpg 1938 Lycopodium lucidulum mature eusporangium. Note the axillary location of sporangial attachment. This is characteristic of some of the less derived of the Lycopodiaceae. Lycophyta, Lycopodiales, sporangium 26
16-049 16-049t.jpg 16-049v.jpg 129 16-049h.jpg 1990 Lycopodium obscurum mature eusporangium. Spores continue to increase in density as they accumulate food stores. The tapetum breaks down as its nutrients dry up in preparation for dehiscence. Note the laminar location of sporangial attachment on the sporophyll. Lycophyta, Lycopodiales, sporangium 27
16-060 16-060t.jpg 16-060v.jpg 193 16-060h.jpg 347 Phylloglossum drummondii tuber and shoot apex. This diminutive close relative of the genus Lycopodium, believed to be a derived member of the Lycopodiales, is quite rare. Slide made at University of Oklahoma Lycophyta, Lycopodiales, tuber 28
16-048 16-048t.jpg 16-048v.jpg 299 16-048h.jpg 1878 Phylloglossum drummondii stobilus. This image of this unusual plant shows a longitudinal section of the cone, displaying a wide range of stages of sporogenesis. Lycophyta, Lycopodiales, sporangia 29
16-047 16-047t.jpg 16-047v.jpg 103 16-047h.jpg 1912 Lycopodium gametophyte with mature antheridia. The antheridia are embedded in this species, with a single layer of cells at the aperture. Antheridia are typically on the underside of the gametophyte. Lycophyta, Lycopodiales, gametophyte, antheridia 30
16-046 16-046t.jpg 16-046v.jpg 130 16-046h.jpg 1975 Lycopodium gametophyte with endophytic fungus, which is characteristic of the slowest growing of the Lycopod gametophytes. The gametophytes of some species may require up to seven years to mature. Lycophyta, Lycopodiales, gametophyte 31
16-044 16-044t.jpg 16-044v.jpg 128 16-044h.jpg 2030 Lycopodium gametophyte with archegonia show the onset of the sexual phase of this long-lived plant. Note the axial row present in the archegonial neck. Lycophyta, Lycopodiales, gametophyte, archegonium, embryogenesis 32
16-045 16-045t.jpg 16-045v.jpg 120 16-045h.jpg 2027 Lycopodium gametophyte with mature archegonia showing the axial row in the archegonial neck, ventral canal cell and interior egg cell. Lycophyta, Lycopodiales, gametophyte, archegonium 33
16-043 16-043t.jpg 16-043v.jpg 209 16-043h.jpg 1658 Lycopodium embryogenesis shows a high diversity of different embryogenetic pathways, which is presumed to be a primitive characteristic. The classical embryo is endoscopic, with the suspensor located under the archegonial neck and the shoot emerging laterally. Lycophyta, Lycopodiales, embryogenesis 34
16-042 16-042t.jpg 16-042v.jpg 125 16-042h.jpg 2025 Lycopodium embryogenesis shows the characteristic young leaves of this plant. The classical embryo is endoscopic, with the suspensor located under the archegonial neck and the shoot emerging laterally. Lycophyta, Lycopodiales, embryogenesis 35
16-062 16-062t.jpg 16-062v.jpg 127 16-062h.jpg 385 Selaginella rhizophore resembles both stems and roots to some degree. Created by an angle meristem in dichotomies, these are enigmatic organs. Lycophyta, Selaginellales, vegetative, sporophyte 35.59
16-063 16-063t.jpg 16-063v.jpg 81 16-063h.jpg 272 Selaginella root with two vascular bundles, presumably close to a dichotomy. Lycophyta, Selaginellales, vegetative, sporophyte 35.57
16-064 16-064t.jpg 16-064v.jpg 123 16-064h.jpg 399 Selaginella rhizome. Note meristeles are located in schizogenous chambers within the stem. Lycophyta, Selaginellales, vegetative, sporophyte 35.52
16-065 16-065t.jpg 16-065v.jpg 126 16-065h.jpg 370 Selaginella rhizome showing a meristele with a plate of xylem. Note trabeculae and Casparian strips indicative of endodermis. Lycophyta, Selaginellales, vegetative, sporophyte 35.53
16-066 16-066t.jpg 16-066v.jpg 98 16-066h.jpg 407 Selaginella apical meristem with apical cell at the tip. Note leaf primordia and young leaves. Lycophyta, Selaginellales, vegetative, sporophyte 35.51
16-068 16-068t.jpg 16-068v.jpg 148 16-068h.jpg 402 Selaginella root with two vascular bundles, presumably close to a dichotomy. Lycophyta, Selaginellales, vegetative, sporophyte 35.58
16-041 16-041t.jpg 16-041v.jpg 243 16-041h.jpg 1726 Selaginella shoot apex. Branching of the apex is dichotomous, but one axis tends to overtop the other (anisotomous) resulting in pseudomonopodial branching. The vascular cylinder is suspended by trabeculae in mature regions of the axis. Lycophyta, Selaginellales, shoot apex, dichotomous branching 35.02
16-067 16-067t.jpg 16-067v.jpg 112 16-067h.jpg 366 Selaginella krausiana anisotomous branching. Although the shoot apex undergoes dichotomous branching, overtopping results in anisotomy and a pseudomonopodial appearance in the plant habit. Lycophyta, Selaginellales, shoot apex, dichotomous branching 35.01
16-037 16-037t.jpg 16-037v.jpg 209 16-037h.jpg 356 Selaginella strobilar axis with adjacent newly initiated and maturing megasporangium and ligule. Lycophyta, Selaginellales, megasporangium 37
16-038 16-038t.jpg 16-038v.jpg 96 16-038h.jpg 349 Selaginella microsporangium within a microsporophyll. A ligule is quite conspicuous subtending the microsporangium. Lycophyta, Selaginellales, microsporangium 38
16-040 16-040t.jpg 16-040v.jpg 128 16-040h.jpg 2339 Selaginella microsporangium with numerous microspores within. Note the layering of the eusporangium. Does this appear to be close to dehiscence? Lycophyta, Selaginellales, microsporangium 39
16-039 16-039t.jpg 16-039v.jpg 137 16-039h.jpg 399 Selaginella microsporangium and microspores. Lycophyta, Selaginellales, microsporangium 40
16-036 16-036t.jpg 16-036v.jpg 170 16-036h.jpg 286 Selaginella young megaspores within a megasporangium. A ligule is quite conspicous subtending the megasporangium. Lycophyta, Selaginellales, megasporangium 41
16-035 16-035t.jpg 16-035v.jpg 185 16-035h.jpg 329 Selaginella young megaspores within a megasporangium. Lycophyta, Selaginellales, megasporangium 42
16-034 16-034t.jpg 16-034v.jpg 60 16-034h.jpg 246 Selaginella young megaspores within a megasporangium. Lycophyta, Selaginellales, megasporangium 43
16-033 16-033t.jpg 16-033v.jpg 250 16-033h.jpg 440 Selaginella megaspores are evident in two adjacent megasporangia. Note the velum and sporophylls. Lycophyta, Selaginellales, megasporangium 44
16-032 16-032t.jpg 16-032v.jpg 146 16-032h.jpg 461 Selaginella megaspores in the megasporangium. Microgametogenesis has progressed to near maturity. It is unclear whether the trilete mark has split, but it may have already germinated. Lycophyta, Selaginellales, megasporangium 45
16-031 16-031t.jpg 16-031v.jpg 198 16-031h.jpg 344 Isoetes storkii plant in Laguna de Po?s in Costa Rica. Photo by Norman Boke. Lycophyta, Isoetales, plant habit 46
16-030 16-030t.jpg 16-030v.jpg 94 16-030h.jpg 317 Isoetes storkii in Laguna de Po?s in Costa Rica. Photo by Norman Boke. Lycophyta, Isoetales, plant habit 47
16-029 16-029t.jpg 16-029v.jpg 157 16-029h.jpg 535 Isoetes storkii in Laguna de Po?s in Costa Rica. Photo by Norman Boke. Lycophyta, Isoetales, plant habit 48
16-028 16-028t.jpg 16-028v.jpg 328 16-028h.jpg 616 Isoetes storkii found in nature. Roy Lent holds a species of Isoetes over the water in Laguna de Po?s in Costa Rica. Photo by Norman Boke. Lycophyta, Isoetales, plant habit 49
16-027 16-027t.jpg 16-027v.jpg 441 16-027h.jpg 899 Isoetes median saggital section showing microphylls, apical meristem, anchor-shaped vascular core and traces (leaf and root). Lycophyta, Isoetales, shoot axis 50
16-026 16-026t.jpg 16-026v.jpg 174 16-026h.jpg 768 Isoetes median saggital section showing surmounting microphylls, apical meristem, anchor-shaped vascular core (characteristic of a sagittal section and traces (leaf and root). Lycophyta, Isoetales, shoot axis, root apex 51
16-025 16-025t.jpg 16-025v.jpg 382 16-025h.jpg 666 Isoetes median frontal section showing surmounting microphylls, apical meristem, vascular core and traces (leaf and root). Note prismatic zone. Lycophyta, Isoetales, shoot axis 52
16-024 16-024t.jpg 16-024v.jpg 372 16-024h.jpg 695 Isoetes corm in longitudinal section showing the vascular attachment of the roots and their endogenous origin from the root apical region from the central vascular core. Lycophyta, Isoetales 53
16-023 16-023t.jpg 16-023v.jpg 198 16-023h.jpg 706 Isoetes corm in cross section. The protostele of this plant is indeed unusually loose. A unifacial cambium forms parenchyma cells and some xylem tracheids. Lycophyta, Isoetales 54
16-022 16-022t.jpg 16-022v.jpg 185 16-022h.jpg 589 Isoetes corm in cross section. This is the basal portion of the corm showing diverging root traces. Lycophyta, Isoetales 55
16-021 16-021t.jpg 16-021v.jpg 188 16-021h.jpg 644 Isoetes corm in cross section. Note the unifacial cambium creating the prismatic zone. The cambium primarily gives rise to parenchyma. Lycophyta, Isoetales 56
16-020 16-020t.jpg 16-020v.jpg 162 16-020h.jpg 663 Isoetes corm in cross section. This unusual corm had three lobes. The center shows its Y-shaped furrow. Lycophyta, Isoetales 57
16-019 16-019t.jpg 16-019v.jpg 413 16-019h.jpg 842 Isoetes corm viewed by basal section showing the ranked rhizotaxis of the roots. Although the roots arise endogenously, it is unusual to have such regular spacings. Lycophyta, Isoetales, rhizotaxis 58
16-018 16-018t.jpg 16-018v.jpg 288 16-018h.jpg 541 Isoetes ligule in cross section is present above the sporangium. Its function is still unclear, even though it is considered to be a characteristic structure of the heterosporous lycopods. Lycophyta, Isoetales, shoot axis 59
16-017 16-017t.jpg 16-017v.jpg 102 16-017h.jpg 316 Isoetes root cross section. This unusual tubular structure with an eccentric positioning of the trace is also characteristic of the roots of the extinct plant Stigmaria. Lycophyta, Isoetales, Stigmarian root 60
16-016 16-016t.jpg 16-016v.jpg 108 16-016h.jpg 389 Isoetes root cross section. This possesses an almost trabecular connection of the root trace. The unusual tubular structure resembles the leaves in some ways. Lycophyta, Isoetales, Stigmarian root 61
16-015 16-015t.jpg 16-015v.jpg 127 16-015h.jpg 280 Isoetes leaf cross section showing the four-chamber nature of the distal part of the leaf. Typical of a microphyllous plant, there is a single trace in the leaf. Lycophyta, Isoetales, leaf 62
16-014 16-014t.jpg 16-014v.jpg 345 16-014h.jpg 671 Isoetes median longitudinal section showing the vascular supply to the maturing sporophylls very nicely. The apical meristem surmounts the vascular core that is located beneath. Note the conspicuous loosely-organized primary xylem. Lycophyta, Isoetales, shoot axis 63
16-013 16-013t.jpg 16-013v.jpg 169 16-013h.jpg 726 Isoetes median longitudinal section showing immature microphylls and apical meristem. The vascular core is located beneath, with primary xylem conspicuous in this view. Lycophyta, Isoetales, shoot axis 64
16-012 16-012t.jpg 16-012v.jpg 324 16-012h.jpg 695 Isoetes median longitudinal section showing an early eusporangium developing on the surface of the sporophyll and the apical meristem closeby. Sporophylls protect the apical region. Lycophyta, Isoetales, shoot axis 65
16-011 16-011t.jpg 16-011v.jpg 349 16-011h.jpg 648 Isoetes median longitudinal section showing maturing sporophylls, the apical meristem, and the underlying corm, with its unusual vascular cambium region. Lycophyta, Isoetales, shoot axis 66
16-010 16-010t.jpg 16-010v.jpg 316 16-010h.jpg 568 Isoetes microsporangium containing maturing microspores that are located among the trabecular process of the sporangium. Lycophyta, Isoetales, microsporangium 67
16-009 16-009t.jpg 16-009v.jpg 330 16-009h.jpg 577 Isoetes microsporangium containing maturing microspores that are located among the trabecular process of the sporangium. Lycophyta, Isoetales, microsporangium 68
16-008 16-008t.jpg 16-008v.jpg 284 16-008h.jpg 548 Isoetes megasporophyll with ligule. Although the function of the ligule is not clear, it is characteristic and contains an endodermal layer, suggesting secretory involvement. Many megaspores are evident. Lycophyta, Isoetales, megasporangium 69
16-007 16-007t.jpg 16-007v.jpg 232 16-007h.jpg 391 Isoetes megasporangium containing maturing megaspores, prior to the filling of the cytoplasm. Lycophyta, Isoetales, megasporangium 70
16-006 16-006t.jpg 16-006v.jpg 131 16-006h.jpg 493 Isoetes megasporangium containing maturing megaspores. In Isoetes the spores often have multiple nuclei, indicating that these are in early megagametogenesis. Lycophyta, Isoetales, megasporangium, microsporangium 71
16-005 16-005t.jpg 16-005v.jpg 181 16-005h.jpg 339 Isoetes megasporangium containing megaspores with early stage megagametophytes. Retension and provisioning of the megaspores shows increased of gametophytic tissues. Lycophyta, Isoetales, megasporangium 72
16-004 16-004t.jpg 16-004v.jpg 91 16-004h.jpg 311 Isoetes megagametophyte soon after germination. Swelling of gametophytic tissue occurs along the trilete mark. At this location and along these grooves, archegonia form that will be fertilized by motile sperm, if present. Lycophyta, Isoetales, gametogenesis 73
16-003 16-003t.jpg 16-003v.jpg 146 16-003h.jpg 252 Embryogenesis in Isoetes. Exoscopic embryo gives rise to shoot, leaf, root and foot. The shoot soon emerges through the wall of the gametophyte to establish the young sporophyte. Diagram from Wardlaw, pg. 119 (1955). Lycophyta, Isoetales, embryogenesis 74
16-002 16-002t.jpg 16-002v.jpg 46 16-002h.jpg 152 Equisetum arvense reproductive and vegetative shoots. Sporangiophores are readily visible in the strobilus, as is the basal annulus. Photo taken in May in Bayside, Wisconsin Sphenophyta, Equisetales, sporophyte 75
16-001 16-001t.jpg 16-001v.jpg 62 16-001h.jpg 198 Equisetum arvense has classically dimorphic aerial shoots. Reproductive shoots have strobili just reaching maturity (anthesis) as vegetative axes are becoming conspicuous. Photo taken in May in Bayside, Wisconsin Sphenophyta, Equisetales, sporophyte 76
16-105 16-105t.jpg 16-105v.jpg 157 16-105h.jpg 2151
16-106 16-106t.jpg 16-106v.jpg 124 16-106h.jpg 1484
16-107 16-107t.jpg 16-107v.jpg 143 16-107h.jpg 1764
16-108 16-108t.jpg 16-108v.jpg 183 16-108h.jpg 2184
16-109 16-109t.jpg 16-109v.jpg 159 16-109h.jpg 985
16-110 16-110t.jpg 16-110v.jpg 170 16-110h.jpg 1901
16-111 16-111t.jpg 16-111v.jpg 110 16-111h.jpg 1579
16-112 16-112t.jpg 16-112v.jpg 133 16-112h.jpg 1461
16-113 16-113t.jpg 16-113v.jpg 142 16-113h.jpg 1627
16-114 16-114t.jpg 16-114v.jpg 138 16-114h.jpg 1663
16-115 16-115t.jpg 16-115v.jpg 158 16-115h.jpg 1629
16-116 16-116t.jpg 16-116v.jpg 126 16-116h.jpg 1662
16-117 16-117t.jpg 16-117v.jpg 119 16-117h.jpg 890
16-118 16-118t.jpg 16-118v.jpg 114 16-118h.jpg 1451
16-119 16-119t.jpg 16-119v.jpg 163 16-119h.jpg 1239
16-120 16-120t.jpg 16-120v.jpg 154 16-120h.jpg 1742
16-121 16-121t.jpg 16-121v.jpg 144 16-121h.jpg 1649
16-122 16-122t.jpg 16-122v.jpg 200 16-122h.jpg 2005
16-123 16-123t.jpg 16-123v.jpg 204 16-123h.jpg 1999
16-124 16-124t.jpg 16-124v.jpg 154 16-124h.jpg 481
16-125 16-125t.jpg 16-125v.jpg 97 16-125h.jpg 1120
16-126 16-126t.jpg 16-126v.jpg 82 16-126h.jpg 1265
16-127 16-127t.jpg 16-127v.jpg 252 16-127h.jpg 3072
16-128 16-128t.jpg 16-128v.jpg 230 16-128h.jpg 2926
16-129 16-129t.jpg 16-129v.jpg 162 16-129h.jpg 2376
16-130 16-130t.jpg 16-130v.jpg 139 16-130h.jpg 1148
16-131 16-131t.jpg 16-131v.jpg 83 16-131h.jpg 1083
16-132 16-132t.jpg 16-132v.jpg 123 16-132h.jpg 1297
16-133 16-133t.jpg 16-133v.jpg 77 16-133h.jpg 1089
16-134 16-134t.jpg 16-134v.jpg 119 16-134h.jpg 1282
16-135 16-135t.jpg 16-135v.jpg 142 16-135h.jpg 1468
16-136 16-136t.jpg 16-136v.jpg 119 16-136h.jpg 1377
16-137 16-137t.jpg 16-137v.jpg 198 16-137h.jpg 1442
16-138 16-138t.jpg 16-138v.jpg 70 16-138h.jpg 1111
16-139 16-139t.jpg 16-139v.jpg 275 16-139h.jpg 2275
16-140 16-140t.jpg 16-140v.jpg 260 16-140h.jpg 1447
16-141 16-141t.jpg 16-141v.jpg 134 16-141h.jpg 1791
16-142 16-142t.jpg 16-142v.jpg 257 16-142h.jpg 2876
16-143 16-143t.jpg 16-143v.jpg 331 16-143h.jpg 3248
16-144 16-144t.jpg 16-144v.jpg 148 16-144h.jpg 1814
16-145 16-145t.jpg 16-145v.jpg 213 16-145h.jpg 3738
16-146 16-146t.jpg 16-146v.jpg 157 16-146h.jpg 1875
16-147 16-147t.jpg 16-147v.jpg 149 16-147h.jpg 1963
16-148 16-148t.jpg 16-148v.jpg 162 16-148h.jpg 2122
16-149 16-149t.jpg 16-149v.jpg 148 16-149h.jpg 2572
16-150 16-150t.jpg 16-150v.jpg 133 16-150h.jpg 2028
16-151 16-151t.jpg 16-151v.jpg 160 16-151h.jpg 1818
16-153 16-153t.jpg 16-153v.jpg 135 16-153h.jpg 1678
16-154 16-154t.jpg 16-154v.jpg 191 16-154h.jpg 2289
16-155 16-155t.jpg 16-155v.jpg 144 16-155h.jpg 1544
16-156 16-156t.jpg 16-156v.jpg 153 16-156h.jpg 1342
16-157 16-157t.jpg 16-157v.jpg 131 16-157h.jpg 1704
16-158 16-158t.jpg 16-158v.jpg 172 16-158h.jpg 2553
16-159 16-159t.jpg 16-159v.jpg 230 16-159h.jpg 1910
16-160 16-160t.jpg 16-160v.jpg 77 16-160h.jpg 1273
16-161 16-161t.jpg 16-161v.jpg 163 16-161h.jpg 1888
16-162 16-162t.jpg 16-162v.jpg 258 16-162h.jpg 3457
16-163 16-163t.jpg 16-163v.jpg 111 16-163h.jpg 1131
16-164 16-164t.jpg 16-164v.jpg 81 16-164h.jpg 876
16-165 16-165t.jpg 16-165v.jpg 136 16-165h.jpg 1988
16-335 16-335t.jpg 16-335v.jpg 59 16-335h.jpg 451
16-336 16-336t.jpg 16-336v.jpg 58 16-336h.jpg 427
16-337 16-337t.jpg 16-337v.jpg 59 16-337h.jpg 410
16-338 16-338t.jpg 16-338v.jpg 133 16-338h.jpg 446
16-339 16-339t.jpg 16-339v.jpg 81 16-339h.jpg 534
16-340 16-340t.jpg 16-340v.jpg 40 16-340h.jpg 148
16-341 16-341t.jpg 16-341v.jpg 96 16-341h.jpg 405
16-342 16-342t.jpg 16-342v.jpg 96 16-342h.jpg 669
16-343 16-343t.jpg 16-343v.jpg 92 16-343h.jpg 422
16-344 16-344t.jpg 16-344v.jpg 154 16-344h.jpg 540
16-345 16-345t.jpg 16-345v.jpg 129 16-345h.jpg 536
16-346 16-346t.jpg 16-346v.jpg 347 16-346h.jpg 513
16-347 16-347t.jpg 16-347v.jpg 25 16-347h.jpg 647
16-348 16-348t.jpg 16-348v.jpg 61 16-348h.jpg 661
16-349 16-349t.jpg 16-349v.jpg 115 16-349h.jpg 505
16-350 16-350t.jpg 16-350v.jpg 80 16-350h.jpg 246
16-351 16-351t.jpg 16-351v.jpg 158 16-351h.jpg 997
16-352 16-352t.jpg 16-352v.jpg 64 16-352h.jpg 281
16-353 16-353t.jpg 16-353v.jpg 67 16-353h.jpg 428
16-354 16-354t.jpg 16-354v.jpg 148 16-354h.jpg 667
16-355 16-355t.jpg 16-355v.jpg 100 16-355h.jpg 644
16-356 16-356t.jpg 16-356v.jpg 64 16-356h.jpg 268
16-357 16-357t.jpg 16-357v.jpg 57 16-357h.jpg 458
16-358 16-358t.jpg 16-358v.jpg 198 16-358h.jpg 374
16-359 16-359t.jpg 16-359v.jpg 183 16-359h.jpg 800
16-360 16-360t.jpg 16-360v.jpg 116 16-360h.jpg 874
16-361 16-361t.jpg 16-361v.jpg 99 16-361h.jpg 531
16-362 16-362t.jpg 16-362v.jpg 125 16-362h.jpg 1159
16-363 16-363t.jpg 16-363v.jpg 178 16-363h.jpg 757
16-364 16-364t.jpg 16-364v.jpg 211 16-364h.jpg 966
16-365 16-365t.jpg 16-365v.jpg 238 16-365h.jpg 817
16-366 16-366t.jpg 16-366v.jpg 122 16-366h.jpg 1069
16-367 16-367t.jpg 16-367v.jpg 97 16-367h.jpg 1064
16-368 16-368t.jpg 16-368v.jpg 200 16-368h.jpg 1056
16-369 16-369t.jpg 16-369v.jpg 280 16-369h.jpg 897
16-370 16-370t.jpg 16-370v.jpg 227 16-370h.jpg 780
16-371 16-371t.jpg 16-371v.jpg 118 16-371h.jpg 865
16-372 16-372t.jpg 16-372v.jpg 118 16-372h.jpg 906
16-373 16-373t.jpg 16-373v.jpg 113 16-373h.jpg 799
16-374 16-374t.jpg 16-374v.jpg 134 16-374h.jpg 647
16-375 16-375t.jpg 16-375v.jpg 286 16-375h.jpg 1360
16-376 16-376t.jpg 16-376v.jpg 156 16-376h.jpg 1359
16-377 16-377t.jpg 16-377v.jpg 261 16-377h.jpg 1485
16-378 16-378t.jpg 16-378v.jpg 191 16-378h.jpg 946
16-379 16-379t.jpg 16-379v.jpg 113 16-379h.jpg 420
16-380 16-380t.jpg 16-380v.jpg 208 16-380h.jpg 763
16-381 16-381t.jpg 16-381v.jpg 271 16-381h.jpg 1117
16-382 16-382t.jpg 16-382v.jpg 258 16-382h.jpg 1285
16-383 16-383t.jpg 16-383v.jpg 314 16-383h.jpg 1272
16-384 16-384t.jpg 16-384v.jpg 180 16-384h.jpg 914
16-180 16-180t.jpg 16-180v.jpg 47 16-180h.jpg 189 Equisetum embryo during early development. Sphenophyta, Equisetales, gametophyte 111
16-181 16-181t.jpg 16-181v.jpg 50 16-181h.jpg 196 Equisetum archegonia with eggs Sphenophyta, Equisetales, gametophyte 110
16-182 16-182t.jpg 16-182v.jpg 49 16-182h.jpg 197 Equisetum anteridia with nearly mature sperm cells. Sphenophyta, Equisetales, gametophyte 109
16-183 16-183t.jpg 16-183v.jpg 59 16-183h.jpg 258 Equisetum gametophyte showing placement of archegonia and antheridis Sphenophyta, Equisetales, gametophyte 108
16-184 16-184t.jpg 16-184v.jpg 54 16-184h.jpg 240 Equisetum antheridium at near maturity. Note the single-celled operculum where the sperm cells are released. Sphenophyta, Equisetales, gametophyte 107
16-185 16-185t.jpg 16-185v.jpg 62 16-185h.jpg 246 Equisetum antheridium at near maturity. Sphenophyta, Equisetales, gametophyte 106
16-186 16-186t.jpg 16-186v.jpg 54 16-186h.jpg 210 Equisetum antheridium at near maturity. Sphenophyta, Equisetales, gametophyte 105
16-187 16-187t.jpg 16-187v.jpg 54 16-187h.jpg 212 Equisetum antheridium at near maturity. Sphenophyta, Equisetales, gametophyte 104
16-188 16-188t.jpg 16-188v.jpg 70 16-188h.jpg 262 Equisetum gametophyte showing the organization of the prothallus tissue. Sphenophyta, Equisetales, gametophyte 103
16-189 16-189t.jpg 16-189v.jpg 32 16-189h.jpg 146 Equisetum gametophyte with antheridia. Note rhizoids and marginal placement of gametangia. Sphenophyta, Equisetales, gametophyte 102
16-190 16-190t.jpg 16-190v.jpg 66 16-190h.jpg 274 Equisetum sporangiophore with vascular bundle. Sphenophyta, Equisetales, sporophyte 101
16-191 16-191t.jpg 16-191v.jpg 58 16-191h.jpg 202 Equisetum sproangium with mature spores and elators. Sphenophyta, Equisetales, sporophyte 100
16-192 16-192t.jpg 16-192v.jpg 48 16-192h.jpg 202 Equisetum shoot apex showing apical cell, merophytes and leaf initiation. Sphenophyta, Equisetales, sporophyte 99
16-193 16-193t.jpg 16-193v.jpg 47 16-193h.jpg 194 Equisetum root apex showing apical cell, root axis and root cap. Sphenophyta, Equisetales, sporophyte 98
16-194 16-194t.jpg 16-194v.jpg 76 16-194h.jpg 313 Equisetum root apex showing apical cell, root axis and root cap. Sphenophyta, Equisetales, sporophyte 97
16-195 16-195t.jpg 16-195v.jpg 48 16-195h.jpg 174 Equisetum root vasculature Sphenophyta, Equisetales, sporophyte 96
16-196 16-196t.jpg 16-196v.jpg 62 16-196h.jpg 225 Equisetum root vasculature Sphenophyta, Equisetales, sporophyte 95
16-197 16-197t.jpg 16-197v.jpg 50 16-197h.jpg 193 Equisetum root vasculature Sphenophyta, Equisetales, sporophyte 94
16-198 16-198t.jpg 16-198v.jpg 70 16-198h.jpg 266 Equisetum root vasculature Sphenophyta, Equisetales, sporophyte 93
16-199 16-199t.jpg 16-199v.jpg 51 16-199h.jpg 200 Equisetum root vasculature Sphenophyta, Equisetales, sporophyte 92
16-200 16-200t.jpg 16-200v.jpg 62 16-200h.jpg 242 Equisetum lateral bud Sphenophyta, Equisetales, sporophyte 91
16-201 16-201t.jpg 16-201v.jpg 85 16-201h.jpg 311 Equisetum rhizome Sphenophyta, Equisetales, sporophyte 90
16-202 16-202t.jpg 16-202v.jpg 41 16-202h.jpg 147 Equisetum endodermis with conspicuous Casparian strips. Sphenophyta, Equisetales, sporophyte 89
16-203 16-203t.jpg 16-203v.jpg 44 16-203h.jpg 150 Equisetum vascular bundle. Note location of the endodermis Sphenophyta, Equisetales, sporophyte 88
16-204 16-204t.jpg 16-204v.jpg 48 16-204h.jpg 174 Equisetum stem with carinal and vallecular canals. Sphenophyta, Equisetales, sporophyte 87
16-205 16-205t.jpg 16-205v.jpg 76 16-205h.jpg 247 Equisetum vascular bundle Sphenophyta, Equisetales, sporophyte 86
16-206 16-206t.jpg 16-206v.jpg 34 16-206h.jpg 149 Equisetum stem cross section showing lateral branch apices located opposite the leaf midribs. Sphenophyta, Equisetales, sporophyte 85
16-207 16-207t.jpg 16-207v.jpg 67 16-207h.jpg 229 Equisetum stem showing highly silicified rib. Sphenophyta, Equisetales, sporophyte 84
16-208 16-208t.jpg 16-208v.jpg 41 16-208h.jpg 172 Equisetum shoot apex cross section of apex and lateral branches, showing cortical ribs and fused microphyllous leaves. Sphenophyta, Equisetales, sporophyte 83
16-209 16-209t.jpg 16-209v.jpg 78 16-209h.jpg 287 Equisetum aerial stem cross-section. Sphenophyta, Equisetales, sporophyte 82
16-210 16-210t.jpg 16-210v.jpg 77 16-210h.jpg 168 Equisetum giganteum in Costa Rica, co-starring Roy Lent. Sphenophyta, Equisetales, sporophyte 81
16-211 16-211t.jpg 16-211v.jpg 52 16-211h.jpg 113 Equisetum Sphenophyta, Equisetales, sporophyte 80