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Volume 71, 1942
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Results.

Table I lists the species for which chromosome numbers were established.

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Table I.
Species. Locality. Chromosome Number.
n 2n
Orchidaceae.
 Thelymitra longifolia Tataraimaka 26
Liliaceae.
 Dianella intermedia Tataraimaka 8 16
 Arthropodium candidum Otari 11 22
 A. ccndidum var. purpuratum Rough Peaks, Lake Wakatipu 11 22
  Simpson and Thomson, MS.
 A. cirrhatum Piha 22 44
 Chrysobactron hookeri Mount Torlesse 7 14
Onagraceae.
Epilobium.
Section A: Similes.
Epilobium erectum Queen Charlotte Sound 18 36
E. pubens Governor's Bay 18
E. junceum Governor's Bay 18
E. pallidiflorum Tataraimaka 18
Section B: Microphyllae.
E. chloraefolium Cass 18
E. cockaynianum Botanic Grdns., Christchurch 18
E. alsinoides Tataraimaka 18
E. pictum Hope Valley 18
E. rotundifolium Tataraimaka 18
Section C: Sparsiflorae.
E. nummularifolium Tataraimaka 18
E. pedunculare Cass 18
Section D: Dermatophyllae.
E. crassum Lake Sumner 18
E. microphyllum Cass 18
E. glabellum Mount Torlesse 18
Undescribed Forms.
E. sp., affinities with E. tasmanicum Botanic Grdns., Christchurch 18
E. sp., affinities with E. orassifolium and E. brevipes Botanic Grdns., Christchurch 18
E. sp., affinities with E. melanocaulon Arthurs Pass 18
A-typical, possible Hybrid Forms.
E. nerterioides XE. pedunculare! Cass 18
E. linnaeoidesXE. rotundifolium! Cass 18
E. billardierianum, a-typical Botanic Grdns., Christchurch 18
Ranunculaceae.
Clematis indivisa Tataraimaka 16

Orchidaceae.

Thelymitra longifolia, which occurs also in Australia and Tasmania, has 26 somatic chromosomes, varying in length from 3·2 to 4·9 μ. Two pairs are distinguished by the presence of trabants (Fig. 1). The centromere in all is median or nearly so.

Thelymitra falls into the systematic sub-group Neottieae. For other genera of this group, Gaiser (1930) records chromosome numbers as follows:—

Epipactis n = 12; 2n = 24.
Neottia n = 16, 18.
Spiranthes n = 12.
Gastrodia n = 8–9; 2n = 16–18.
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Picture icon

Fig. 1—Thelymitra longifolia. Somatic metaphase; 2n = 26.
Fig. 2—Dianella intermedia. Somatic metaphase; 2n = 16.
Figs. 3–4—D. intermedia. Metaphase I, anaphase I; n = 8.
Fig. 5—Arthropodium candidum. Somatic metaphase; 2n = 22.
Fig. 6—A. candidum var. purpuratum. Somatic metaphase; 2n = 22.
Fig. 7—Arthropodium cirrhatum. Somatic metaphase; 2n = 44.

Liliaceae.

Dianella intermedia. Eight chromosomes were counted in first metaphase and anaphase of meiosis (Figs. 3–4) and 16 chromosomes in mitotic metaphases (Fig. 2). The somatic complement consists of 8 pairs of M * chromosomes, with a range in length from approximately 4·5 to 9·3 μ.

Arthropodium. Aceto-carmine preparations of pollen mother-cells of A. candidum and the bronze-leaved variety of A. candidum (var. purpuratum Simpson and Thomson, MS.) showed n = 11 in

[Footnote] *M = chromosomes with median or submedian centromere.

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metaphase I and II of meiosis (Figs. 8–9). A. cirrhatum was found to be relatively tetraploid with n = 22 (Fig. 10). It is a much larger plant than the former varieties, which fact agrees with their polyploid relationship. These findings were verified from somatic counts. The somatic chromosomes are too small for detailed study, but in both diploid forms there may be distinguished a larger pair of chromosomes (4·5 μ) with approximately median centromere, and a shorter pair (2·2 μ). The remainder of the complement ranges between these two extremes (Figs. 5–6). The centromeres are all median or nearly so.

Picture icon

Fig. 8—A. candidum. Metaphase I; n = 11.
Fig. 9—A. candidum, bronze-leaved var. Metaphase I; n = 11.
Fig. 10—A. cirrhatum. Metaphase I n = 22.
Fig. 11—Chrysobactron hookeri. Somatic metaphase; 2n = 14.

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The bronze-leaved variety of A. candidum has another long pair (3·6 μ). The tetraploid, A. cirrhatum, shows quite clearly 4 large chromosomes (4·5 μ), two very short pairs (1·8–2·3 μ), and with less certainty two pairs of intermediate length (3·6 μ). No quadrivalents were seen in meiosis, so that this species may be assumed to be an allo-tetraploid.

Picture icon

Fig. 12—Epilobium erectum. Somatic metaphase; 2n = 36.
Fig. 13—E. junceum. Metaphase I; n = 18.
Fig. 14—E. chloraefolium. Metaphase I; n = 18.
Fig. 15—E. nummularifolium. Metaphase I; n = 18.
Fig. 16—E. crassum. Metaphase I; n = 18.
Fig. 17—Clematis indivisa. Somatic metaphase; 2n = 16.

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Chrysobactron hookeri. The limited amount of pollen mother-cell material available was poorly fixed, but side-views of metaphase I indicated the presence of 7 bivalents, with 2–4 chiasmata per bivalent. The chiasmata are random and unterminalised.

A study of somatic plates verified the presence of 7 pairs of chromosomes, 2n = 14 (Fig. 11). There are 5 M pairs, M1–M5, with a range in length from 12·5 to 18·5 μ; and 2 S* pairs, S1–S2, ranging from 10–11 μ in length. The S1 pair is further distinguished by the presence of a trabant; while one of the S2 chromosomes shows a lacuna, which in several cells was seen in both S2 chromosomes.

Onagraceae.

Epilobium. Representatives of all four systematic groups have n = 18 chromosomes (Figs. 13–16), and this applies also to 3 a-typical, possibly hybrid and to 3 undescribed, forms. It may be noted that the endemic division Dermatophyllae, in particular the very distinct E. crassum, conforms to the rule for the remaining divisions, and that all agree in this respect with species of the northern hemisphere: the 6 species and 4 hybrids recorded by Gaiser (1930) have also n = 18, 2n = 36 chromosomes. The small size of the chromosomes, with a range of only 1·3–2·7 μ, in root-tips (Fig. 12), did not invite a detailed study; no irregularities were observed in meiosis.

Ranunculaceae.

Clematis indivisa has 5 M chromosome pairs and 3 S pairs, making a somatic complement of 2n = 16 (Fig. 17). Those with median centromere cannot be paired off with certainty and vary in length from approximately 6·6 to 9 μ. In the S pairs, S1 and S2 are about 5 μ long, S3 slightly shorter, but the 3 pairs are further differentiated by a progressive decrease in the size of the short arm from S1 through S2 to S3, where the centromere is almost terminal.

C. indivisa is one of 9 endemic species. Its somatic chromosome number agrees with that established for Clematis species elsewhere by Langlet (Gaiser, 1930) and Meurman and Therman (1939). The chromosome complement of C. indivisa approximately corresponds in morphology also to that of the species studied by Meurman and Therman (1939). These authors record also tetraploid and hexaploid species.

No pollen mother-cell material was available.

[Footnote] *S = chromosomes with sub-terminal centromere.