Chapter 1: The Characeae Plant

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divided into 3-5 secondary rays and 3-5 tertiary rays. d) Nitella hyalina with two whorls of
branchlets at the node (a longer, primary whorl of 8 branchlets, and a smaller, inner,
secondary whorl of 7 branchlets), with the branchlets divided into 3-6 secondary rays, 3-5
tertiary rays and 3-4 quaternary rays. Scale bars = 5 mm.
Figure 1.4 Branchlet morphology in the different genera of charophyte plants. a) Chara, b)
Lamprothamnium, c) Nitella d) Tolypella.
Figure 1.5 Branchlet nodes and gametangia of Chara spp. In Chara the oogonium (female) is
above the antheridium, and bract cells, bracteoles and cortical filaments arise from the nodal
complex.
Figure 1.6 General morphology of Chara australis (r186, r612, r692). a) whole plant
showing main axis and whorls of branchlets. b) whorl of branchlets from a male plant with 6
branchlets in a whorl and antheridia at the branchlet nodes. c) whorl of branchlets from a
female plant with 6 branchlets in a whorl with oogonia at the base of the whorl and on the
branchlet nodes. d) oogonium with coronula of appressed cells, and spiral cells surrounding
the internal egg cell. e) branchlet node with bract cells and two oogonia, f) base of branchlet
whorl with relatively elongate stipulodes, g) base of whorl with obscure stipulodes and two
basal oogonia.
Figure 1.7 Lamprothamnium macropogon (r809, r822) a) whole thallus showing whorls of
branchlets, downward pointing stipulodes and verticillate bract cells on the branchlets. b)
fertile whorl with antheridia on the branchlets and oogonia inside the base of the whorl, or
beside the antheridia. c) internal view of whorl with a single antheridium squeezed among the
oogonia. d) branchlet and bract cell morphology. e) Lamprothamnium papulosum (r729) with
conjoined gametangia, the antheridium above the oogonium.
Figure 1.8 Lamprothamnium sp aff. succinctum from Australia (r 272). a) whole plant
showing elongated internodes and few, small stipulodes and bract cells. b) whorl of
branchlets with antheridia and oogonia on the branchlets. c) detail of basal gametangia,
oogonia within the whorl, a single antheridium below the whorl in the place of a stipulode. d)
antheridium at a branchlet node with two bract cells. e) two young oogonia at a branchlet
node with three bract cells.
Figure 1.9 Lamprothamnium inflatum (r901, r902, r905). a) Shoot of highly inflated
specimen with almost spherical second segments on the branchlets, obscure stipulodes and
contracted apicies. b) elongated shoot. c) whorl of fertile branchlets with oogonia and