A 
Chromosome Numbers in Characeae from die South Pacific 1 
Arland Hotchkiss 2 
ABSTRACT: This study of a total of 18 collections represents the first sampling 
of chromosome numbers in the charophytes from New Caledonia, Fiji, and Samoa. 
Chromosome counts were obtained for the first time for material of Lamprotham- 
nium {Char a) succinctum, and the count supports the transfer to the genus Lampro- 
thamnium. Chromosome counts consistent with earlier reports are those of 14 for 
the dioecious taxa included in Char a corallina {Char a australis, Protochara australis, 
Chara fulgens ) by Wood, and 18 for Nitella acuminata. Not in accord with some 
earlier reports are the counts of 18 for Nitella hyalina, 18 for Nitella pseudoflabel- 
lata (including N. mathuata ) , 18 for Nitella furcata, and 28 for Chara fibrosa. 
The presence of somatic pairing of chromosomes is noted in Chara fibrosa, and 
the extent and importance of polyploidy in the charophytes is recalled. 
The extensive collections of charophytes 
made by Dr. R. D. Wood during the course of 
an expedition ranging from Australia to New 
Zealand and islands of the South Pacific in 1960- 
61 will form an important basis for studies on 
the Characeae of these regions. As already re- 
ported (Wood, 1962 b) the collections include 
plant specimens gathered and preserved espe- 
cially for cytological examination. These the 
writer was privileged to receive, together with 
the accompanying field notes and identifications 
which follow the revision of the group by Wood 
(1962^). This paper, the first in a series to record 
the chromosome numbers and related cytological 
findings in the Wood collections, is concerned 
with the plants from New Caledonia, Fiji, and 
Samoa, and is concurrent with detailed tax- 
onomic treatments of these plants by Wood 
(1963, 1965). Although the present paper is 
complementary in nature no attempt has been 
made to support all the taxonomic conclusions 
in Woods revision of the Characeae. 
PLANT MATERIALS AND METHODS 
For the cytological studies, fertile plants with 
growing tips bearing young stages of game- 
tangial development were selected and fixed in 
the field. In dioecious species only the male 
plants are required for the young antheridia used 
in making chromosome counts. Fixation with 
freshly prepared acetic-alcohol was done in the 
usual manner. The specimens were then trans- 
ferred to 70% ethanol and shipped in sealed 
vials by airmail to Louisville, where they were 
stored under refrigeration. Chromosome counts 
were made from mitoses found in squashed 
preparations of filaments dissected from the an- 
theridia and stained with aceto-orcein. Usually a 
series of preparations were needed before a count 
could be determined with certainty. Drawings 
were made with the aid of a camera lucida. . 
Four vials of specimens were received from 
New Caledonia, 12 from Fiji, and 1 from Samoa, 
each of which yielded chromosome counts. All 
these specimens and the permanent slides of 
chromosome preparations made from them are 
deposited in the Herbarium of the University of 
Louisville; other parts of these collections are 
deposited elsewhere (Wood, 1962 b) . 
The collection data listed below include the 
notes supplied by Dr. Wood as to dates, locali- 
ties, ecology, and collecting numbers. The cy- 
tology collection numbers (CYT) were included 
with the notes and on the cork stoppers of the 
1 This study was supported in part by the National 
Science Foundation. Manuscript received August 29, 
1963. 
2 Department of Biology, University of Louisville, 
Louisville, Kentucky. 
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