The short and straightforward answer is no, watercress and morning glory are not the same plant. The confusion arises from the use of 'water morning glory,' also known as water spinach or Chinese watercress, which is an edible plant from the Ipomoea genus, belonging to the bindweed family (Convolvulaceae). True watercress, on the other hand, is a member of the mustard family (Brassicaceae), the same family as kale and cabbage.
The Botanical Breakdown
To fully understand why these plants are different, we must look at their scientific classification. This is the most accurate way to distinguish them, as common names can often overlap and cause confusion, as is the case here.
- Watercress (Nasturtium officinale): As a member of the family Brassicaceae, it is a true cress, related to other peppery greens. Its scientific name is important to know for correct identification.
- Water Morning Glory (Ipomoea aquatica): This is the edible species that causes the name confusion. It belongs to the family Convolvulaceae. The many species of ornamental morning glories, like Ipomoea purpurea, also belong to this family, but their seeds can be toxic.
Physical Characteristics: Leaves, Stems, and Flowers
Visually, there are clear distinctions between the two plants that can help you identify them correctly.
- Watercress: This plant typically has hollow stems and green, pinnate leaves with multiple, rounded, or lobed leaflets. The leaves have a deep, glossy green appearance. It produces small, white, four-petaled flowers arranged in clusters.
- Water Morning Glory: This semi-aquatic plant has long, hollow, vine-like stems. The leaves are generally heart-shaped or arrowhead-shaped and can be larger than watercress leaves. It produces trumpet-shaped flowers that are often white or pinkish-purple, typical of the morning glory family.
Culinary Uses and Flavor Profile
Their culinary applications and tastes are also quite different, owing to their distinct biological makeup.
- Watercress: Prized for its pungent, peppery, and slightly spicy flavor, watercress is a favorite in salads, sandwiches, and soups. It is best harvested before it flowers to maintain its best flavor.
- Water Morning Glory: Known for its tender shoots and leaves with a mild, slightly sweet flavor. It is a staple in Southeast Asian cuisine, particularly in stir-fried dishes where it can absorb flavors beautifully. It is often stir-fried with garlic and chili, or used in soups.
Nutritional Value and Potential Risks
Both are nutritious leafy greens, but they offer different nutritional benefits and potential safety considerations.
Nutritional Comparison
| Feature | Watercress | Water Morning Glory (Water Spinach) |
|---|---|---|
| Botanical Family | Brassicaceae (Mustard Family) | Convolvulaceae (Bindweed Family) |
| Key Vitamins | A, C, and K | A, C, E, K, and B6 |
| Key Minerals | Calcium, potassium, iron | Iron, calcium, potassium |
| Antioxidants | High levels of flavonoids and isothiocyanates | High levels of plant-based antioxidants |
| Flavor | Pungent, peppery, spicy | Mild, slightly sweet |
Potential Toxicity
While watercress is generally safe to eat raw or cooked, it's crucial to be aware of the toxicity risks associated with the morning glory family. Many ornamental varieties of morning glory (Ipomoea species) produce seeds containing lysergic alkaloids, which are toxic to humans and pets if ingested in large quantities and can cause hallucinations. The edible water morning glory (Ipomoea aquatica) is not known for this toxicity, but people should always be careful to identify the plant correctly and source it responsibly. Consuming wild watercress from potentially polluted water sources can also carry a risk of liver fluke contamination.
Conclusion: A Matter of Botanical Identity
In summary, despite the confusing common name of 'Chinese watercress' sometimes being applied to water morning glory, they are entirely separate plants from different botanical families with distinct features, flavors, and risks. Watercress is a peppery mustard family green, while the edible water morning glory is a vining plant from the bindweed family with a milder taste. Proper identification is key for anyone consuming or cultivating these plants, especially given the potential toxicity of certain non-edible morning glory species. By understanding their botanical roots and key characteristics, you can avoid culinary confusion and ensure both safety and satisfaction. For more information on plant toxicity, consult the ASPCA's database of toxic and non-toxic plants.
Frequently Asked Questions (FAQs)
Q: What is the botanical family of watercress? A: Watercress belongs to the Brassicaceae family, which also includes other cruciferous vegetables like kale, broccoli, and cabbage.
Q: Is water morning glory edible? A: Yes, the species Ipomoea aquatica, known as water morning glory, water spinach, or kangkong, is a common and edible vegetable in Southeast Asian cuisine.
Q: How can I tell watercress and water morning glory apart? A: Watercress has smaller, rounded leaflets and white flowers, while water morning glory has heart-shaped or arrowhead leaves and produces larger, trumpet-shaped flowers.
Q: Are all morning glory plants poisonous? A: No, but many ornamental morning glory species, particularly their seeds, can be toxic and contain hallucinogenic compounds. The edible water morning glory is not toxic, but care must be taken with identification.
Q: Where do watercress and water morning glory grow? A: Watercress prefers cool, running water, while water morning glory thrives in tropical and subtropical climates, growing in wet soil or aquatic environments like rivers and canals.
Q: What does watercress taste like? A: Watercress has a distinctive, pungent, and peppery flavor. Its taste is often described as spicy or slightly bitter, similar to other mustard family greens.
Q: What does water morning glory taste like? A: Water morning glory has a mild, slightly sweet, and earthy flavor. It is known for its tender shoots and is excellent at absorbing the flavors of sauces and spices it's cooked with.
