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Table 2 Morphological characters and dimensions (µm), cardinal temperatures (°C) and temperature-growth relations (mm/d) on V8A of Phytophthora castanetorum, P. tyrrhenica, P. tubulina, P. vulcanica and their closest relatives in phylogenetic Clades 7a and 12, respectively. Most discriminating characters are highlighted in bold.

From: Multiple new cryptic pathogenic Phytophthora species from Fagaceae forests in Austria, Italy and Portugal

  P. castanetorum P. tubulina P. quercina P. tyrrhenica P. vulcanica P. uliginosa P. europaea P. flexuosa
No. of isolates 9 5 10b 7 5 3a 7a 3a
Sporangia ovoid, subglobose, obpyriform, globose, (ellipsoid, distorted) ovoid, obpyriform, distorted, (globose, subglobose, ellipsoid, limoniform) subglobose, ovoid, obpyriform, peanut, ampulliform, distorted elongated ellipsoid, elongated ovoid, elongated limoniform ovoid, ellipsoid, (obpyriform, pyriform) ellipsoid, ovoid, peanut-shaped, (obpyriform, limoniform) ovoid, obpyriform, ellipsoid, (subglobose), ovoid, ellipsoid, (obpyriform, limoniform)
apex 77.4 % papillate, 14.9 % semipapillate; 7.7 % nonpapillate, 4.9 % curved 78 % mono-, bi- or tripapillate; 13.3 % semi-papillate; 8.7 % non-papillate, 4.9 % curved all papillate, some bi- and tripapillate; often curved nonpapillate nonpapillate nonpapillate nonpapillate, often pointed  
lxb mean 47.0±5.7 × 36.6±3.7 51.6±9.8 × 37.3±7.0 42.4±11.5 × 29.3±13.8 68.4±1.7 × 28.9±1.9 57.3±8.7 × 34.5±4.2 67.0±8.5 × 42.4±6.4 63.7±16.9 × 44.6±8.3 56.1±7.4 × 36.7±5.2
range of isolate means 44.2–48.1 × 35.4–38.3 43.3–57.8 × 31.2–45.0 36.0–49.2 × 23.3–33.7 66.1–70.0 × 27.5–31.9 53.6–61.0 × 31.8–36.4 65.7–70.3 × 30.9–44.4 50.0–78.9 × 36.7–51.2 53.3–58.6 × 33.9–39.4
total range 27.1–74.5 × 18.1–47.9 29.5–98.5 × 19.2–59.2 18.8–112.5 × 13.8–17.5 45.3–110.2 × 16.2–39.4 35.5–80.7 × 22.5–42.9 41.1–85.0 × 24.8–56.9 23.6–124.3 × 21.9–67.3 34.9–74.8 × 22.8–49.7
l/b ratio 1.29 ± 0.15 1.40 ± 0.18 1.45 ± 0.37 2.40 ± 0.18 1.67 ± 0.22 1.60 ± 0.19 1.42 ± 0.19 1.54 ± 0.18
caducity - rare - - - - - -
lateral insertion 37.7 % 22.4 % frequent      
exit pores 7.0 ± 1.1 6.4 ± 1.2 6.5 ± 1.2 12.1 ± 2.4 17.0 ± 3.0 15.4 ± 3.4 19.3 ± 4.7 19.7 ± 3.4
zoospore cysts 9.2 ± 1.0 11.7 ± 1.8 9.5 (7.1–12.9) 14.6 ± 2.3 10.0 ± 1.2 11.9 ± 1.8 15.3 ± 2.0 13.3 ± 1.3
Breeding system homothallic homothallic homothallic homothallic homothallic homothallic homothallic homothallic
Oogonia         
mean diam 32.9 ± 3.0 29.2 ± 4.4 29.4 ± 4.1 37.2 ± 3.3 35.8 ± 3.6 46.2 ± 7.5 37.3 ± 5.4 36.8 ± 3.3
range of isolate means 30.5–34.4 25.4–30.1 25.8–32.0 36.8–40.9 33.6–36.5 41.6–53.3 34.4–39.9 36.0–38.3
total range 24.3–41.7 16.5–42.5 19.0–45.0 25.0–39.3 23.0–16.0 17.9–65.5 19.2–48.4 25.7–12.8
tapering base 61.3% (40–86 %) 48.7 % (30–78 %) n.a. - 37.3 % (8–60 %) - 60.0 % (52–81 %) 47.9 % (32–58 %)
elongated 65.4 % (50–82 %) 59.5 % (36–86 %) 45 % (10–86 %) - 44.8 % (8–80 %) - 21.3 % (12–34 %) 19.7 % (4–36 %)
tubular - 24.5% (21–28 %) - - - - - -
excentric 6.7 % (2–20 %) 5.0 % (2–8 %) n.a. - 20.9 % (9–46 %) - 4.0 % (0–8 %) 5.3 % (2–10 %)
smooth-walled 100 % 100 % 100 % 100 % 100 % 100 % 100 % 34.4% (19–48 %)
Oospores plerotic oospores 64.3 % (50–83 %) 44 % (24–76 %) mostly aplerotic >99% (99–100 %) 27.3 % (10–15 %) 30.0 % (12–46 %) 46.3 % (38–53 %) >99% (99–100 %)
mean diam 28.7 ± 2.6 26.1 ± 3.7 24.7 ± 2.6 33.7±1.3 30.5 ± 3.2 41.3±6.1 33.2 ± 5.3 32.2 ± 2.7
Total range 21.9–38.8 15.7–36.3 18.0–30.0 24.6–39.9 19.7–38.2 12.5–55.0 16.3–45.1 22.7–37.7
wall diam 3.1 ± 0.49 2.0 ± 0.6 2.4 ± 0.56 2.9 ± 1.5 2.4 ± 0.4 4.2 ± 0.7 2.5 ± 0.7 3.1 ± 0.5
oospore wall index 0.51 ± 0.05 0.38 ± 0.08 0.44 ± 0.1 0.41 ± 0.03 0.40 ± 0.06 0.49 ± 0.07 0.38 ± 0.06 0.47 ± 0.06
Abortion rate 21.5 % (18–29 %) 72.3 % (40–91 %) <10% 5 % (3–7 %) 52.8 % (0–80 %) 6.2 % (3–10 %) 24.9 % (18–31 %) 1.7% (1–2 %)
Antheridia 99 % paragynous 100 % paragynous 100 % paragynous 100 % paragynous 4.7 % amphigynous 100 % paragynous 100 % paragynous 100 % paragynous
size 14.0±2.3 × 10.2±1.6 14.9±3.1 × 10.9±1.7 16.6±6.3 × 12.7±2.5 16.9±4.6 × 12.8±0.13 16.3±3.1 × 12.6±2.3 16.9±3.1 × 13.3±2.5 13.6±2.6 × 10.8±2.1 13.4±2.1 × 10.0±1.7
Chlamydospores globose - rare, in some isolates - - - - -
mean diam 29.5 ± 4.9 (17.7–47.0)   17–35      
Hyphae Sympodial branching with protruding tip of mother hypha Sympodial branching with protruding tip of mother hypha Sympodial branching with protruding tip of mother hypha   Often inflated tubular or club-shabed    Coralloid
Hyphal aggregations - - - - +   - -
Hyphal swellings in water; globose, subglobose, limoniform; some catenulate in water; subglobose, triangular; some catenulate   in water; subglobose, irregular, catenulate in water; subglobose, irregular, catenulate in water; subglobose, irregular, catenulate   
Maximum temperature 25–<30 25–<30 27.5 25–<30 25–<30 25 30–<35 35
Optimum temperature 20 20 25 25 15 20 25 25
Growth rate at optimum 2.9 ± 0.91 1.7 ± 1.0 3.7 1.1 ± 0.4 1.0 ± 0.1 1.2 ± 0.2 4.9 ± 0.53 4.7 ± 0.61
Growth rate at 20°C 2.7 ± 0.75 1.7 ± 1.0 3.3 1.5 ± 0.3 0.9 ± 0.04 1.2 ± 0.2 4.4 ± 0.59 4.4 ± 0.56
  1. − = character not observed; + = character observed; n.a. = not available.
  2. a Data from Jung et al. (2017b).
  3. b Morphological and morphometric data from Jung et al. (1999); standard deviations of all morphometric data, oospore wall diameter and oospore wall index calculated from original dataset.