Leaf Key to Native Oaks of Maryland

(Quercus genus) 10/01/12 (C) Chris Puttock

Download PDF Winter Key to Native Oaks of Maryland
Download PDF Leaf Key to Native Oaks of Maryland

A key to the oak species of Maryland based upon mature leaves exposed to full sunlight 

• Lamina margins sinuate, dentate, or shallowly to deeply lobed; lobes and apices without awns; secondary veins lacking hair tufts (domatia)-- go to A. White Oaks
  
• Lamina margins entire, or shallowly to deeply lobed; lobes and apices with awns; secondary veins with hair tufts (domatia)-- go to B. Red and Black Oaks
  

A. White Oaks 

1. Lamina margin sinuate or dentate, with a lobe or point for each parallel secondary vein reaching the margin; sinuses less than one-eighth distance to midvein -- (go to 2) 
1. Lamina with well-defined deep lobes; each secondary vein not ending in a lobe; one or more sinuses extending more than one-quarter distance to the midvein -- (go to 5) 

2. Lamina with few secondary veins (8 or less); base cuneate, acute --  Q. prinoides 
2. Lamina with many secondary veins (9 or more); base truncate, obtuse to rounded -- (go to3) 

3. Lamina sinuate, with obtuse to rounded apices -- Q. prinus 
3. Lamina dentate, with acute apices --  (go to 4) 

4. Lamina base obtuse to truncate; yellowish-green pubescent or glabrous below -- Q. michauxii 
4. Lamina base rounded; silvery white pubescent below -- Q. muehlenbergii 

5. Lamina glabrous below -- (go to 6) 
5. Lamina tomentose below -- (go to 7) 

6. Lamina with finger-like lobes and narrow sinuses; lobe apices rounded --  Q. alba 
6. Lamina with wide lobes and spreading sinuses; lobe apices acute to obtuse -- Q. lyrata 

7. Lamina mostly elliptical; sinuses extending one-quarter to one-half distance to the midvein -- Q. bicolor 
7. Lamina obovate; sinuses extending more than one-half distance to the midvein -- (go to 8) 

8. Petiole mostly less than 15mm long -- Q. stellata 
8. Petiole mostly more than 15mm long --Q. macrocarpa 

B. Red and Black Oaks 

1. Petioles predominantly less than 20(-25)mm long (go to 2) 
1. Petioles predominantly more than (20-)25mm long -- (go to 6) 

2. Lamina lacking lobes; apex terminating with a terminal awn -- (go to 3) 
2. Lamina variously lobed; each lobe terminating in an awn -- (go to 4) 

3. Lamina narrowly elliptical to linear-- Q. phellos 
3. Lamina narrowly obovate to oblanceolate.-- Q. imbricaria 

4. Lamina deeply lobed throughout; obovate, ovate to narrowly ovate in outline Q. ilicifolia 
4. Lamina shallowly lobed, and only distally; obovate to oblanceolate in outline --  (go to 5) 

5. Lamina obovate in outline, almost as wide as long -- Q. marilandica 
5. Lamina narrowly obovate to oblanceolate in outline, at least twice as long as wide -- Q. nigra

6. Lamina usually with 1–2(–3) awn per lateral lobe -- (go to 7) 
6. Lamina with 3–10 awns per lateral lobe -- (go to 8) 

7. Lamina pale rusty pubescence below; (2–)3–5 lateral lobes per side and the terminal lobe shorter than the lateral lobes -- Q. pagoda 
7. Lamina pale gray pubescence below; 1–2(–3) lateral lobes per side and the terminal lobe longer than the lateral lobes -- Q. falcata 

8. Lamina lobe sinuses less than 2/3 to the midvein -- Q. rubra 
8. Lamina lobe sinuses more than 2/3 to the midvein -- (go to 9) 

9. Lamina margin of basal lobes somewhat recurved; middle lobes at right angles to the midvein -- Q. palustris 
9. Lamina margin of basal lobes straight to ascending; middle lobes ascending, acute to the midvein -- (go to10) 

10. Petiole less than one-third the length of the lamina --  Q. shumardii 
10. Petiole more than one-third the length of the lamina -- (go to 11) 

11. Lamina light green above; glabrous except for axillary tufts below; lobes widely expanded distally -- Q. coccinea 
11. Lamina dark green above; pubescent becoming glabrous in late summer; lobes slightly expanded distally -- Q. velutina 

© C.F.Puttock September 25, 2012