How to Spot Poison Ivy, According to a Scientist

iStock
iStock

If you're a former scout, you've probably heard the rhyme “leaves of three, let it be.” This mnemonic device, used to steer intrepid outdoorspeople away from poisonous ivy and oak, is generally sound advice for ensuring you don’t come home with a nasty rash. Not all three-leaved plants are the enemy, though, and several harmless plants are often confused with poison ivy.

Microbiologist John Jelesko shared some tips with NPR for identifying this pernicious plant. First, it helps to know what you’re up against. Poison ivy is a master of disguise and can take many different shapes and sizes. It can appear in small patches, take the form of creeping vines or a bush, and can even mimic the appearance of a tree it has wrapped itself around. The leaves can have either “smooth, jagged, or lobed edges” and may or may not bear white or greenish berries.

If the plant has thorns, you can be sure it’s not poison ivy, whose mode of attack is a little more stealthy. In the city, Jelesko had found that climbing vines are the more common form; look out for ground-creeping vines in forested areas. While there are exceptions to this rule, Jelesko’s research found that poison ivy tends to take different forms depending on the landscape.

A longer middle stem and a hairy vine are also signs that you could be dealing with poison ivy. If you have a plant in your garden that you can’t identify, you can conduct a “black dot test” to see if it’s poison ivy. Put on a pair of gloves, tear a leaf in half, and place the sap on a sheet of white paper. If it’s urushiol oil (the rash-causing chemical in poison ivy), it will turn black within 30 minutes.

Sometimes, even our best efforts to identify poison ivy may fail. If you think you may have brushed up against it, don’t panic—take a shower within a few hours of contact. That should keep your chance of developing a rash at a minimum.

[h/t NPR]

Amazon's Best Black Friday Deals: Tech, Video Games, Kitchen Appliances, Clothing, and More

Amazon
Amazon

This article contains affiliate links to products selected by our editors. Mental Floss may receive a commission for purchases made through these links.

Black Friday is finally here, and Amazon is offering great deals on kitchen appliances, tech, video games, and plenty more. We will keep updating this page as sales come in, but for now, here are the best Amazon Black Friday sales to check out.

Kitchen

Instant Pot/Amazon

- Instant Pot Duo Plus 9-in-115 Quart Electric Pressure Cooker; $90 (save $40)

- Keurig K-Cafe Special Edition; $190 (save $30)

- Ninja OS301 Foodi 10-in-1 Pressure Cooker and Air Fryer; $125 (save $75)

- Nespresso Vertuo Next Coffee and Espresso Machine by Breville; $120 (save $60)

- KitchenAid KSMSFTA Sifter with Scale Attachment; $95 (save $75)

- Keurig K-Mini Coffee Maker; $60 (save $20)

- Cuisinart Bread Maker; $80 (save $97)

- Anova Culinary Sous Vide Precision Cooker; $139 (save $60)

- Aicook Juicer Machine; $35 (save $15)

- JoyJolt Double Wall Insulated Espresso Mugs - Set of Two; $14 (save $10)

- Longzon Silicone Stretch Lids - Set of 14; $16 (save $11)

- HadinEEon Milk Frother; $37 (save $33)

Home Appliances

Roomba/Amazon

- iRobot Roomba 675 Robot Vacuum with Wi-Fi Connectivity; $179 (save $101)

- ASAKUKI 500ml Premium Essential Oil Diffuser; $22 (save $4)

- Facebook Portal Smart Video Calling 10 inch Touch Screen Display with Alexa; $129 (save $50)

- Bissell air320 Smart Air Purifier with HEPA and Carbon Filters; $280 (save $50)

- Oscillating Quiet Cooling Fan Tower; $59 (save $31)

- TaoTronics PTC 1500W Fast Quiet Heating Ceramic Tower; $55 (save $10)

- Vitamix 068051 FoodCycler 2 Liter Capacity; $300 (save $100)

- Ring Video Doorbell; $70 (save $30)

Video games

Sony

- Marvel's Spider-Man: Game of The Year Edition for PlayStation 4; $20 (save $20)

- The Legend of Zelda: Link's Awakening; $40 (save $20)

- Hyrule Warriors: Age of Calamity; $50 (save $10)

- Marvel's Avengers; $25 (save $33)

- The Last of Us Part II for PlayStation 4; $30 (save $30)

- LEGO Harry Potter: Collection; $15 (save $15)

- Ghost of Tsushima; $40 (save $20)

- BioShock: The Collection; $20 (save $30)

- The Sims 4; $24 (save $20)

- God of Warfor PlayStation 4; $10 (save $10)

- Days Gonefor PlayStation 4; $20 (save $6)

- Luigi's Mansion 3 for Nintendo Switch; $40 (save $20)

Computers and tablets

Microsoft/Amazon

- New Apple MacBook Pro 16 inches with 512 GB; $2149 (save $250)

- Microsoft Surface Laptop 3 with 13.5 inch Touch-Screen; $1200 (save $400)

- Lenovo ThinkPad T490 Laptop; $889 (save $111)

- Amazon Fire HD 10 Tablet (64GB); $120 (save $70)

- Amazon Fire HD 10 Kids Edition Tablet (32 GB); $130 (save $70)

- Apple iPad Mini (64 GB); $335 (save $64)

- Vankyo MatrixPad S2 Tablet; $120 (save $10)

Tech, gadgets, and TVs

Apple/Amazon

- Apple Watch Series 3 with GPS; $120 (save $79)

- Seneo Wireless Charger, 3 in 1 Wireless Charging Station; $16 (save $10)

- SAMSUNG 75-inch Class Crystal 4K Smart TV; $998 (save $200)

- Nixplay 2K Smart Digital Picture Frame 9.7 Inch Silver; $238 (save $92)

- All-New Amazon Echo Dot with Clock and Alexa (4th Gen); $39 (save $21)

- MACTREM LED Ring Light 6" with Tripod Stand; $16 (save $3)

- Amazon Fire TV Stick with Alexa Voice Remote; $28 (save $12)

- DR. J Professional HI-04 Mini Projector; $93 (save $37)

Headphones and speakers

Beats/Amazon

- Beats Solo3 Wireless On-Ear Headphones; $120 (Save $80)

- Apple AirPods Pro; $169 (save $50)

- Anker Soundcore Upgraded Bluetooth Speaker; $22 (save $8)

- Powerbeats Pro Wireless Earphones; $175 (save $75)

- JBL Boombox; $280 (save $120)

Movies and TV

HBO/Amazon

- Game of Thrones: The Complete Series; $115 (save $89)

- Jurassic World 5-Movie Set; $23 (save $37)

- Deadwood: The Complete Series; $42 (save $28)

- Back to the Future Trilogy; $15 (save $21)

Toys and Games

Amazon

- Awkward Family Photos Greatest Hits; $15 (save $10)

- Exploding Kittens Card Game; $10 (save $10)

- Cards Against Humanity: Hidden Gems Bundle; $14 (save $5)

- LOL Surprise OMG Remix Pop B.B. Fashion Doll; $29 (save $6)

- LEGO Ideas Ship in a Bottle 92177 Expert Building Kit; $56 (save $14)

Furniture

Casper/Amazon

- Casper Sleep Element Queen Mattress; $476 (save $119)

- ZINUS Alexis Deluxe Wood Platform Bed Frame; $135 (save $24)

- ROMOON Dresser Organizer with 5 Drawers; $59 (save $11) 

- AmazonBasics Room Darkening Blackout Window Curtains; $26 (save $5)

- Writing Desk by Caffoz; $119 (save $21)

- SPACE Seating Office Support Managers Chair; $112 (save $116)

- Rivet Globe Stick Table Lamp; $53 (save $17)

- Christopher Knight Home Merel Mid-Century Modern Club Chair; $188 (save $10)

- Walker Edison Furniture Industrial Rectangular Coffee Table; $121 (save $48)

Beauty

Haus/Amazon

- MySmile Teeth Whitening Kit with LED Light; $21 (save $12) 

- Cliganic USDA Organic Lip Balms Set of Six; $6 (save $4)

- HAUS LABORATORIES By Lady Gaga: LE RIOT LIP GLOSS; $7 (save $11)

- Native Deodorant for Men and Women Set of Three; $25 (save $11) 

- BAIMEI Rose Quartz Jade Roller & Gua Sha; $14 (save $3)

- Honest Beauty Clearing Night Serum with Pure Retinol and Salicylic Acid; $20 (save $8)

- WOW Apple Cider Vinegar Shampoo and Hair Conditioner Set; $30 (save $5) 

- La Roche-Posay Effaclar Purifying Foaming Gel Cleanser; $15 (save $5)

- wet n wild Bretman Rock Shadow Palette; $9 (save $6)

- EltaMD UV Daily Tinted Face Sunscreen Moisturizer with Hyaluronic Acid; $25 (save $6)

Clothes

Ganni/Amazon

- Ganni Women's Crispy Jacquard Dress; $200 (save $86) 

- The Drop Women's Maya Silky Slip Skirt; $36 (save $9)

- Steve Madden Women's Editor Boot; $80 (save $30)

- adidas Women's Roguera Cross Trainer; $40 (save $25)

- Line & Dot Women's Elizabeth Sweater; $74 (save $18)

- Levi's Men's Sherpa Trucker Jacket; $57 (save $41)

- Adidas Men's Essentials 3-Stripes Tapered Training Joggers Sweatpants; $28 (save $12)

- Timex Men's Weekender XL 43mm Watch; $32 (save $20)

- Ray-Ban Unisex-Adult Hexagonal Flat Lenses Sunglasses; $108 (save $46) 

- Reebok Men's Flashfilm Train Cross Trainer; $64 (save $16)

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The 20 Most Valuable Companies in the World

The Apple store on Fifth Avenue in New York City.
The Apple store on Fifth Avenue in New York City.
Laurenz Heymann, Unsplash

It seems like the most valuable companies should be those whose products and services we use on a near-daily basis. And according to Forbes’s most recent list, they are: The top five highest-valued brands in the world are Apple, Google, Microsoft, Amazon, and Facebook.

The annual study is based on a complex mixture of metrics that cover revenue and earnings, tax rates, price-to-earnings ratios, and capital employed. Since the data is from 2017 to 2019, the list doesn’t reflect how the coronavirus pandemic has affected the companies in question. That said, it does reflect what many have long assumed: that Big Tech is running laps around all the other industries. The top five are all considered technology companies, as are four others in the top 20 (Samsung, Intel, Cisco, and Oracle). Other companies aren’t in the technology category, but they own lucrative offshoots that are. Disney, in seventh place with an estimated value of $61.3 billion, falls under the “leisure” umbrella—but Disney+ itself would likely be marked “technology.” (Netflix is.)

The list isn’t completely devoid of time-tested classics that don’t involve software or hardware. Coca-Cola edged out Disney by about $3 billion to take sixth place; Toyota placed 11th with a brand value of $41.5 billion; and McDonald’s just cracked the top 10 with $46.1 billion. Louis Vuitton, Nike, and Walmart all also made the top 20.

Just because a brand ranked high on this year’s list doesn’t necessarily mean it’s doing well (and vice versa). Facebook, for example, suffered a 21-percent decrease in brand value compared to Forbes’ 2019 list—the largest loss of all 200 companies included in the study. Netflix’s brand value, on the other hand, jumped a staggering 72 percent from 2019 to 2020. With an estimated $26.7 billion value, it still missed the top 20 by six spots.

See Forbes’s top 20 below, and check out the full list here.

  1. Apple // $241.2 billion
  1. Google // $207.5 billion
  1. Microsoft // $162.9 billion
  1. Amazon // $135.4 billion
  1. Facebook // $70.3 billion
  1. Coca-Cola // $64.4 billion
  1. Disney // $61.3 billion
  1. Samsung // $50.4 billion
  1. Louis Vuitton // $47.2 billion
  1. McDonald’s // $46.1 billion
  1. Toyota // $41.5 billion
  1. Intel // $39.5 billion
  1. Nike // $39.1 billion
  1. AT&T // $37.3 billion
  1. Cisco // $36 billion
  1. Oracle // $35.7 billion
  1. Verizon // $32.3 billion
  1. Visa // $31.8 billion
  1. Walmart // $29.5 billion
  1. GE // $29.5 billion

[h/t Forbes]