CANNABACEAE, Martinov, 1820

Wheeler, Elisabeth A., Manchester, Steven R. & Baas, Pieter, 2023, A late Eocene wood assemblage from the Crooked River Basin, Oregon, USA, PaleoBios 40 (14), pp. 1-55 : 29

CANNABACEAE / MORACEAE WOOD TYPE 1

FIG. 14A–F

Description— Growth rings present, marked by radially narrow fibers, and marginal axial parenchyma. Narrow latewood vessels in the marginal parenchyma bands ( Fig. 14A, B ).

Wood diffuse-porous; vessels solitary and in radial multiples of 2–3 ( Fig. 14A, B ); mean tangential diameter of vessels 164 µm ( SD =27), range 118–218 µm; 6–10 vessels per mm 2. Perforation plates simple; intervessel pits alternate ( Fig. 14C ), horizontal diameter 9–12 µm. Vessel-ray parenchyma pits similar in size to the interves- sel pits, simple or with reduced borders ( Fig. 14D ). Vessel element lengths short, <350 µm; vessel element end walls slightly inclined. Thin-walled tyloses present.

Fibers thin- to thick-walled, non-septate, pitting not observed.

Axial parenchyma marginal, scanty paratracheal to vasicentric ( Fig. 14A, B ); strands of 4–8 cells.

Rays (1–2) 3–6 seriate, mostly 4–5-seriate; uniseriate rays rare; average multiseriate ray height 489 ( SD =180) µm, range 191–842 µm. Rays homocellular, composed of procumbent cells, and heterocellular with 1-2 marginal rows of square/upright cells, rarely more ( Fig. 14F ); sheath cells in some rays ( Fig. 14C ); 4–7 per mm.

Storied structure, oil/mucilage cells, and crystals not observed.

Specimen— UF 278-84894, estimated maximum diameter 20+ cm.

Occurrence— Dietz Hill ( UF 278).

Comparisons with extant woods— Our initial search of InsideWood used: presence of distinct growth ring boundaries (1p), wood diffuse-porous (5p), absence of exclusively solitary vessels, distinct vessel arrangement, and radial multiples of ten or more common (6a, 7a, 8a, 9a, 10a), presence of simple perforation plates and alternate intervessel pits that are not minute or small (13p, 22p, 24a 25a), vessel-ray parenchyma pits with reduced borders (31p), non-septate fibers with simple pits (61p, 66p), scanty paratracheal, vasicentric axial parenchyma and marginal parenchyma present (78p, 79p. 89p), maximum ray width 4–10-seriate (98p), rays not> 1mm or of two sizes (102, 103a), rays not composed of all upright cells or markedly heterocellular or with intermixed procumbent and square/upright cells (105a, 108a 109a), sheath cells present (110p), storied structure and oil/mucilage cells absent (118a, 119a, 120a, 124a 125a 126a), radial canals required absent (130e). If no mismatches are allowed, this particular search only returns Morus spp.

Allowing one mismatch returns Morus spp. again, two species of Celtis ( Cannabaceae ), and Petersianthus Merrill (1916) ( Lecythidaceae A. Rich. (1826b) . The last genus can be excluded because its parenchyma is aliform-confluent and diffuse-in-aggregates to narrow bands. According to Kew’s Plants of the World ( POWO 2023), there are 17 accepted species of Morus and 66 accepted species of Celtis .

Of the images of diffuse-porous woods of Moraceae in InsideWood, it looked as if only Morus insignis Bureau (1873) (Uw 24976) had axial parenchyma distribution similar to this Dietz Hill wood, all others had more abun- dant axial parenchyma. In the Chinese Atlas ( Itoh et al. 2022), diffuse-porous Morus also appear to have more abundant axial parenchyma. The diffuse-porous Mo. macroura Miq. (1851) (TWTw 13642) and Celtis africana Burm. f. (FPAw 31962, Kw IND.845) both appear to have narrow vessel elements embedded in seemingly marginal parenchyma. has narrow vessel elements embedded in seemingly marginal parenchyma.

This wood has a combination of features found in Celtis and Morus .

Comparisons with fossil woods— When no mismatches are allowed, the only matches in the fossil wood database were two descriptions with most features coded as unknowns. If one mismatch is allowed, Scottoxylon eocenicum ( Urticales , family unknown) from the middle Eocene Clarno Nut Beds is returned ( Wheeler and Manchester 2002), but it has more axial parenchyma as does the other result, Dracontomeloxylon palaeomangiferum Prakash (1979) from the Deccan Intertrappean Beds. There does not appear to be a previously described fossil wood that is a good match for this Dietz Hill wood. Because of this wood's resemblance to both Celtis ( Cannabaceae ) and Morus ( Moraceae ) we refer to it as Cannabaceae / Moraceae Wood Type 1.

Figures

Figure 14. Urticales. Cannabaceae/Moraceae Wood Type 1. UF 278-87894. A, B. Wood diffuse-porous, vessels solitary and in radial multiples; marginal parenchyma, TS. C. Alternate intervessel pitting, polygonal in outline, simple perforation plates, ray with sheath cells, TLS. D. Vessel to parenchyma pits, similar in size to intervessel pitting with reduced borders, RLS. E. Rays predominantly multiseriate, 1-2-seriate rays rare, TLS. F. Ray body cells procumbent, marginal row of upright/square cells, RLS. Scale bars‒500 µm in A; 200 µm in B, E; 100 µm in F; 50 µm in C, D.