Pyracantha

This journal entry compares a few different keys to Pyracantha. I prepared it in order to facilitate identification of some Pyracantha from Monterey County, California.

A case study would be in distinguishing P. koidzumii and P. fortuneata. Nesom (2010) distinguishes these based on leaf margin, with P. koidzumii margins entire or with only very shallow teeth. I find Zika (2012) to be a bit more ambiguous, apparently only admitting shallow teeth near the tip of the leaf for koidzumii. Lance & Zika (2015) follows suit. Feng et al. (2021) use a different character altogether: abaxial pubescence, with P. koidzumii being minutely pubescent vs P. fortuneata being glabrous.

Feng et al. (2021) A taxonomic revision of the Pyracantha crenulata complex (Rosaceae, Maleae). Phytotaxa 478 (2): 239–252.
Key is for taxa occurring in China, so it excludes P. atalatioides, for example.
1a. Corymbs dense; pedicel 1–2 mm long; hypanthium abaxially densely tomentose --> 2
1b. Corymbs loose; pedicel 4–10 mm long; hypanthium abaxially glabrous or slightly pubescent --> 3
2a. Leaf apically acute, blade oblong to oblong-obovate; petiole 4–6(–9) mm long; branches usually unarmed --> P. inermis
2b. Leaf apically obtuse or truncate, blade obovate to obovate-elliptic; petiole to 2 mm long; branches with short thorns --> P. densiflora
3a. Leaves abaxially densely tomentose --> P. angustifolia
3b. Leaves abaxially glabrous or pubescent --> 4
4a. Leaf blade abaxially minutely pubescent --> P. koidzumii
4b. Leaf blade abaxially glabrous --> P. crenulata complex (P. crenulata, P. fortuneata, P. loureiroi)

Lance & Zika. 2015. Pyracantha. Flora of North America.
1 Leaf margins crenulate, crenulate-serrulate, or serrulate (at least 1/2 length of blades) --> 2
1' Leaf margins usually entire, rarely remotely serrulate distally or with minute teeth near apices --> 4
2 Leaf blades oblanceolate or obovate, apices obtuse, emarginate, or short-apiculate. --> Pyracantha fortuneana
2' Leaf blades lanceolate, oblong, oblanceolate, ovate-lanceolate, elliptic, or ovate, apices usually acute or short-apiculate --> 3
3 Young twigs gray-hairy, glabrescent later; hypanthia finely hairy. --> Pyracantha coccinea
3 Young twigs brown-hairy, glabrescent later; hypanthia glabrous. --> Pyracantha crenulata
4 Calyces and leaf abaxial surfaces persistently gray-tomentose. --> Pyracantha angustifolia
4 Calyces and leaf abaxial surfaces brown- or yellowish brown-puberulent when young, glabrescent --> 5
5 Leaf blades elliptic, oblong, or oblong-obovate (usually widest near middle), apices obtuse, apiculate, or aristate, abaxial surfaces glaucescent. --> Pyracantha atalantioides
5 Leaf blades oblanceolate or narrowly obovate (usually widest distal to middle), apices usually truncate or retuse, abaxial surfaces pale green but not glaucescent. --> Pyracantha koidzumii

Zika. 2012. Pyracantha. The Jepson Manual: Vascular Plants of Califorina, 2nd ed.

1. Leaf generally serrate to crenate over much of margin --> 2

2. Leaf tip obtuse or ± notched, oblong-obovate to obovate; pedicels glabrous or sparsely hairy in flower; stones ± black --> P. fortuneana
   2' Leaf tip generally acute, generally oblong-elliptic to lanceolate, elliptic, or ovate (rarely oblanceolate in some Pyracantha coccinea); pedicels generally hairy in flower; stones brown --> 3

3. Hypanthium hairy in flower; new growth gray-hairy; leaves on vigorous shoots generally elliptic --> [P. coccinea]
   3' Hypanthium glabrous in flower; new growth rusty-hairy; leaves on vigorous shoots narrow-oblong-elliptic --> [P. crenulata]
   1' Leaf generally entire or with a few well separated low or rounded teeth toward tip --> 4

4. Sepals in fruit, young leaves densely gray-hairy abaxially; leaves generally narrowly oblong
   to ± oblanceolate --> P. angustifolia
   4' Sepals in fruit, young leaves ± glabrous or ± rusty- or yellow-brown-hairy abaxially; leaves narrowly oblanceolate to elliptic --> 5

5. Leaves generally widest near middle, tips generally obtuse or abruptly soft-pointed; petals generally ovate, 4–5 mm --> [P. atalantioides]
   5' Leaves generally widest above middle, tips generally truncate or ± notched; petals generally round or widely elliptic, 3–4 mm --> P. koidzumii

Nesom (2010) Pyracantha (Rosaceae) naturalized in Texas and the southeastern United States. Phytoneuron 2010-2: 1-6.

1. Leaf blades 4–8 mm wide, abaxially densely and persistently tawny-puberulent to puberulentvillous, margins entire --> Pyracantha angustifolia

2. Leaf blades 5–25 mm wide, abaxially glabrous or quickly glabrescent, margins entire or crenate to
   crenulate-serrate or apiculate. --> 2

3. Leaf margins entire or occasionally 1–3(5) very shallow teeth per side, apices rounded to truncate,
   usually retuse --> Pyracantha koidzumii

4. Leaf margins usually crenate to crenulate or crenulate-serrate with numerous teeth or apiculae,
   apices mostly acute or obtuse to rounded or truncate, rarely retuse. --> 3

5. Leaf blades narrowly elliptic to rhombic-elliptic, sometimes narrowly so, apices acute, margins
   crenate to crenulate --> Pyracantha coccinea

6. Leaf blades narrowly obovate to obovate-oblanceolate (widest above the middle) or oblong to elliptic (widest at the middle), apices obtuse to rounded, truncate, or retuse, margins very shallowly to minutely serrulate, crenulate-serrate, or apiculate, less commonly apparently entire in P. atalantioides.--> 4
7. Leaf blades narrowly obovate to obovate-oblanceolate (widest above the middle)--> Pyracantha fortuneana
8. Leaf blades oblong to elliptic (widest at the middle) --> Pyracantha atalantioides

Publicado el 14 de diciembre de 2023 a las 02:28 AM por fredwatson