Source: MOBOT, Tropicos.org^[1]

Source: Royal Botanic Gardens, Kew.^[2]

Lactuca virosa var. cruenta
Source: Royal Botanic Gardens, Kew.^[3]

Large trichome found on the lower epidermis near the vein showing lignified cell observed at 400x with Acidified Chloral Hydrate Glycerol Solution.
Source: Elan M. Sudberg, Alkemist Laboratories^[4]

Dark brown latex observed at 400x with Acidified Chloral Hydrate Glycerol Solution.
Source: Elan M. Sudberg, Alkemist Laboratories^[5]

Lactuca virosa HPTLC ID - Natural Product Reagent + PEG UV 365 nm

Wild Lettuce (leaf) (Lactuca virosa)

Lane Assignments Lanes, from left to right (Track, Volume, Sample):

1. 2 μL Rutin, Caffeic Acid, Hyperoside, Chlorogenic Acid ~ 0.1% in Methanol
2. 3 μL Lactuca virosa-1 (leaf)
3. 3 μL Lactuca virosa-2 (herb)
4. 3 μL Lactuca virosa-3 (leaf)
5. 3 μL Lactuca virosa-3 (leaf)
6. 3 μL Lactuca virosa-4 (herb)
7. 3 μL Lactuca virosa-5 (herb)
8. 2 μL Rutin, Caffeic Acid, Hyperoside, Chlorogenic Acid ~ 0.1% in Methanol

Reference materials used here have been authenticated by macroscopic, microscopic &/or TLC studies according to the reference source cited below held at Alkemists Laboratories, Costa Mesa, CA. 

Stationary Phase Silica gel 60, F254, 10 x 10 cm HPTLC plates 

Mobile Phase ethyl acetate: formic acid: glacial acetic acid: water [10/0.9/0.9/2] 

Sample Preparation Method 0.3g+3mL CH3OH sonicate/heat @~50° C ~ 1/2 hr 

Detection Method Natural Product Reagent + PEG -> UV 365 nm 

Reference see Lactuca_virosa_-_Alkemists_Laboratories.jpg

Source: Elan M. Sudberg, Alkemist Laboratories ^[6]