Sophora microphylla ( Aiton, 1789 )

Pole, Mike, 2022, A vanished ecosystem: Sophora microphylla (Kōwhai) dominated forest recorded in mid-late Holocene rock shelters in Central Otago, New Zealand, Palaeontologia Electronica (a 1) 25 (1), pp. 1-41 : 11

Sophora microphylla ( Aiton, 1789)

Figure 9

Material. Present in 75% of the shelters with dry vegetation. Shelter-001: LX2714; Shelter-001: LX2716; Shelter-003: LX5416, LX5420, LX5422; Shelter-005: LX5399, LX5401, LX5407, LX5552; Shelter-006: LX5553, LX5557, LX5558, LX5565; Shelter-007: SL 6599; Shelter-008: SL 6668; Shelter-009: LX3225, LX3226; Shelter-012: LX3141, SL 6715; Shelter-014: LX3168, SL 6628, SL 6629; Shelter-017: SL 6578, SL 6602, SL 6603, SL 6619; Shelter-018: LX3008, LX3018; Shelter-020: LX2954; Shelter-021: LX3148, SL 6711; Shelter-022: LX3353; Shelter-024: SL 6605, SL 6606, SL 6607; Shelter-025: LX3178, SL 6676, SL 6679; Shelter-026: SL 6709; Shelter-027: LX2973, SL 6461, SL 6463; Shelter-028: LX2940; Shelter-029: LX5798; Shelter-030: LX2473, LX2966; Shelter-031: LX2953, LX5500, LX5501; Shelter-032: LX2915, LX2916, LX2986; Shelter-033: LX2949, LX5494, LX5495, LX5496, LX5497; Shelter-034: LX2963; Shelter-036: LX2977; Shelter-037: LX2942; Shelter-038: LX2978; Shelter-039: LX5571; Shelter-040: LX3249; Shelter-041: SL 6487; Shelter-042: LX2604; Shelter-043: LX2597; Shelter-046: LX2566, LX2573; Shelter-047: LX3277, LX3279; Shelter-049: LX3332; Shelter-050: LX2590; Shelter-053: LX3286; Shelter-054: LX3284; Shelter-055: LX3316; Shelter-057: LX2531; Shelter-058: SL 6484; Shelter-059: SL 6455, SL 6456; Shelter-060: LX3295; Shelter-061: LX3301; Shelter-062: LX3274; Shelter-063: SL 6529; Shelter-065: LX3261, LX3312; Shelter-067: LX3258; Shelter-068: SL 6501; Shelter-070: LX2608, LX2612; Shelter-071: SL 6436; Shelter-073: SL 6511; Shelter-074: LX2539; Shelter-075: LX2595; Shelter-076: LX3006; Shelter-077: LX2550, LX2554; Shelter-078: LX3358, LX3359; Shelter-079: LX5865, LX5866, LX5667; Shelter-082: LX2439, LX2449, LX2451, LX2896; Shelter-086: LX3300; Shelter-087: LX3306, LX3309; Shelter-088: LX3318; Shelter-089: LX3354, LX3356; Shelter-090: LX3266; Shelter-091: LX3013; Shelter-092: LX2893, LX3002; Shelter-095: LX2889; Shelter-096: LX2880; Shelter-097: LX2461; Shelter-098: LX3022; Shelter-099: LX3028; Shelter-100: LX2897, LX2900, LX2904; Shelter-101: LX2906, LX2909, LX2911; Shelter-102: LX2523; Shelter-103: LX2517, LX2518; Shelter-105: LX3138; Shelter-106: LX5623, LX5624, LX5625; Shelter-110: LX3109; Shelter-111: LX5505; Shelter-113: LX5521; Shelter-114: LX5851, LX5852, LX5853, LX5854, LX5855, LX5856, LX5859, LX5860; Shelter-115: LX5671.

Remarks. The cuticle of both adaxial and abaxial epidermal surfaces is easily recognizable. The abaxial has persistent, deeply staining trichomes, as well as subdued but numerous papilae, and relatively small, poorly staining stomata. The adaxial has simple, deeply staining trichome attachments, surrounded by radially elongate epidermal cells. Eight species of Sophora are recognized in New Zealand ( Heenan et al., 2001). Based on the cuticle morphology, leaf size, and the current distribution of S. microphylla (which is widespread over the region, albeit often rare or restricted) identification of the shelter material is made with that species. However, McGlone and Wood (2019, p. 2) identified seeds from the Gibraltar Rock shelter as S. prostata ( Buchanan, 1884) , stating that they were “sufficiently distinctive that we can be confident” that the species was present. S. prostata is currently unknown in the study area, and there are no records south of the Waitaki River (i.e., within 100 km of the area, Heenan et al., 2018), although it is conceivable that its absence from the southern end of New Zealand might be attributed to removal by a late Holocene fire. McGlone and Wood (2019) did not expand on how seeds of S. prostata and S. microphylla could be distinguished, but the leaflets of S. prostata reach about 4 mm long (Breitweieser et al., 2010), while those of S. microphylla range from about 4.5-12.5 mm long. The two species are also clearly distinguishable on cuticle morphology. S. prostrata does not have the trichome bases, which are so prominent in S. microphylla , and there is a much clearer ring of subsidiary cells surrounding the stoma (pers. obs.). On both characters all the leaves found in the present study are regarded as S. microphylla , and unless otherwise indicated, further mention of ‘ Sophora’ means S. microphylla .

Figures

FIGURE 9. Sophora cuticle morphology (Transmitted light microscopy). A. View of S. microphylla stomatal (abaxial) surface showing deeply stained trichome bases, papillae, and stomatal complexes (LX2799, Shelter-96, scale bar equals 100 μm). B. View of S. microphylla stomatal (abaxial) surface of less-stained specimen, but still showing relatively well-stained trichome bases, papillae, and stomatal complexes (LX2590, Shelter-50, scale bar equals 100 μm). C. Detail to show stomatal complexes, partly obscured by irregular papillae (LX3052, from Coprolite-26, scale bar equals 40 μm). D. View of S. microphylla non-stomatal (adaxial) surface, with deeply staining trichome attachment at right (LX3052, Coprolite-26, scale bar equals 40 μm). E. View of S. microphylla non-stomatal (adaxial) surface, with four deeply staining trichome attachments. Note the characteristic radiating surrounding epidermal cells (LX3006, Shelter-76, scale bar equals 100 μm). F. View of basal portion of S. microphylla leaf mid-rib (abaxial surface), showing dense trichome attachment sites (LX3106, Shelter-39, scale bar equals 100 μm). G. View of another style of S. microphylla cuticle morphology from basal portion of the leaf mid-rib (abaxial surface), showing dense trichome attachment sites, and thinner cuticle on either side (LX3052, Coprolite-26, scale bar equals 100 μm). H. Abaxial cuticle of Sophora prostrata. Note clearly different from S. microphylla in absence of trichome attachment sites, and distinct ring of subsidiary cells around the stoma (OPH5491, scale bar equals 100 μm).