Most identification problems come down to a handful of concrete differences in size, leaf, and flower, so here are the ones that separate the pairs people ask about most, along with what monocot means, what ponics means, and why a store pineapple had seeds in it.
How do I tell a monocot from a dicot?
Four features do it, and the leaves are the quickest.
Seed leaves. A monocot seed carries one cotyledon, the food storage structure that feeds the seedling. A dicot carries two. A bean is the demonstration everyone uses: soak one, and it splits cleanly into two halves with the tiny stem, root, and first leaves tucked between them. A corn kernel is a monocot and will not split that way.
Leaf veins. This is the practical field test. Monocot leaves run their veins in parallel lines down the leaf. Dicot leaves have veins that branch and form a net.
Flower parts. Monocot flowers usually build in threes or multiples of three. Dicot flowers usually run to fours or fives and their multiples.
Familiar examples. On the monocot side: grasses and corn, plus irises, palms, and the lilies. On the dicot side: tomatoes, squash, and zinnias.
So a sweet pea, with its netted leaf veins and its five petalled pea flower, is a dicot, and you can confirm it yourself by soaking a seed overnight and splitting it.
Amaranth or celosia?
They are relatives, both in the amaranth family, and they look nothing alike once you know what to watch for.
Amaranth carries purplish flowers in a long drooping cluster, grows about three to five feet tall, and has a coarse, substantial look to it.
Celosia, also sold as cockscomb or Chinese woolflower, has plumed or crested flower heads that look like tangled masses of yarn, in vivid pink, orange red, gold, and crimson. It reads as tropical. Dwarf strains stay around ten inches, and full sized ones reach two and a half to three feet.
A tall willowy plant with red, yellow, and orange tops is celosia, most likely one of the plumed types.
Orange jessamine: which Murraya do I want for a hedge?
Both get sold under the same common name, which is where the confusion starts.
Murraya paniculata is the faster grower and the usual hedging plant. It reaches six to fifteen feet tall and about as wide.
The dwarf form, often sold as M. exotica, is slower, more upright, and denser, topping out near six feet tall and four feet wide. Its foliage is a lighter green with smaller, stiffer leaflets.
For a ninety foot run of hedge at five feet high in a warm zone, take M. paniculata. It will fill in far sooner and it takes clipping to your height easily. The dwarf is the better choice only if you want a low hedge you almost never cut.
Carolina cherry laurel: 'Bright 'n Tight' or 'Compacta'?
Both are selections of Prunus caroliniana chosen for tighter growth than the wild species.
'Compacta' is denser and smaller leaved than the species, growing to roughly ten feet tall and four to six feet wide, and it tolerates drought, wind, and heat.
'Bright 'n Tight' is the tightly branched screening plant, with notably glossy deep green foliage and a clean look. It grows moderately to about eight to ten feet tall and six to eight feet wide, more if you never cut it, and it takes occasional shearing well. Full sun to part sun.
For a formal clipped hedge the difference is small; for a screen you shear once or twice a year, 'Bright 'n Tight' is the one nurseries push for good reason.
One thing to know before planting either near children or livestock: this plant is poisonous. The crushed leaves smell like maraschino cherries, which is charming and misleading, and that scent comes from cyanide compounds released as the foliage is bruised or wilts. The black cherry like fruit is eaten by birds but is not safe for people. Wilted clippings are more dangerous than fresh growth, so bag prunings and keep them away from grazing animals rather than tossing them over a fence, and site the plant where a child is not going to be sampling the berries.
Mimosa, powder puff, and royal poinciana
These three get mixed up constantly because all three carry fine ferny foliage and fluffy flowers.
Mimosa, Albizia julibrissin, is a deciduous legume family tree of twenty to forty feet, low branching, open, and spreading. The leaves are bipinnately compound, six to twenty inches long, with twenty to sixty leaflets, which is what gives the feathery look. Bark is light brown and smooth, and young stems are lime green before turning brown and speckled with lenticels. Fragrant pink pompom flowers about an inch and a half across appear from May into July at the tips of the current year's twigs. The pods are flat, straw colored, and about six inches long with five to ten oval seeds, and they hang on through winter. It is hardy in roughly zones 6 through 9.
Powder puff, Calliandra, is in the same legume family and is not the same plant. It sprawls rather than forming a tree, keeps compound evergreen foliage that is glossy green in good health, and blooms mainly in spring and summer, most often in red. It needs full sun, tolerates most soils but dislikes salt spray near the coast, and needs little care once established. Its hardiness stops at about zone 9, so in a zone 6 garden it is a container plant that overwinters indoors, not a landscape tree.
Royal poinciana, Delonix regia, sometimes called the flame tree, is the big showy one. It grows thirty to forty feet tall with an umbrella shaped canopy often wider than the tree is high, and over several weeks across spring and into summer it carries clusters of flame red flowers four to five inches across. Each flower has four spreading spoon shaped scarlet petals about three inches long plus one upright petal marked with yellow and white. Its leaves are twice pinnate and twelve to twenty inches long, with twenty to forty pairs of primary leaflets each divided again into ten to twenty pairs. The pods are dark brown, woody, and flat, up to two feet long.
Where two of them grow side by side, as happens in Florida, the flowers are the reliable difference: small pink pompoms mean mimosa, large flat scarlet flowers mean royal poinciana.
Two cautions on this group. Mimosa is invasive across much of the southeastern and mid Atlantic United States, seeding heavily into roadsides and stream banks, so check your state or county list before planting one, moving one, or passing along seedlings. And do not eat any part of any of them on the strength of a family resemblance. Some traditions use Albizia julibrissin flowers, but the plant is not a food crop, edibility has not been established for Calliandra species, and a shared family says nothing at all about whether a plant is safe to eat. The same family contains plants that will make you seriously ill.
Variegated liriope or variegated flax lily?
Both are strap leaved edging plants sold in the same part of the nursery, and in a Florida garden they behave differently enough to matter.
Variegated liriope, Liriope muscari 'Variegata', is a border grass look alike with grassy foliage edged in creamy yellow. It makes tidy clumps around nine to twelve inches tall and carries purple blue flower spikes, rather like grape hyacinths, in early fall. It wants rich moist soil and, in Florida heat, does best in full shade or with no more than a few hours of morning sun.
Variegated flax lily, the Dianella usually sold under that name, grows taller at around eighteen inches, carries small lavender blue flowers, and follows them with blue berries in spring. It takes the same shade to light morning sun and is noticeably more drought tolerant once established.
Both are easy and long lived, and both are cut back rather than fussed over. Choose liriope for a low, dense, formal edge in a spot you can water, and flax lily where you want more height and less watering. The flax lily berries are ornamental only and are not for eating.
Why did a store bought pineapple have seeds in it?
Nothing has gone wrong. Pineapples are bromeliads, and bromeliads can set seed, though commercial fruit is usually seedless because the plantings are clones that cannot pollinate each other. Occasional pollination, often by hummingbirds or bats where flowering fields sit near wild relatives, leaves a scattering of hard brown seeds tucked in behind the eyes.
The reason you read that pineapples are grown from the top of the fruit is that they are. Commercial propagation is all by cuttings, that is crowns, slips, and suckers, because seed is slow and does not come true.
You can still grow the seeds you found. They need no pretreatment. Sow them on the surface of a moist seed starting mix, because light is one of their germination requirements, then hold the container between 60 and 70 degrees F. Cover the container with plastic wrap to hold humidity and take the cover off as soon as sprouts appear. Expect germination to take about ninety days, so do not throw the pot out at week six. A seed grown plant may never fruit, but it makes a perfectly good houseplant, and the wait is the whole point of the exercise.
What does the ponics in hydroponics mean?
It comes from Greek. Hudor is water and ponos is work or labor, so hydroponics translates roughly as water working.
In modern use the word usually gets defined as growing plants without soil, but a sharper definition is growing plants by supplying every nutrient they need in the water. That distinction matters for a science project, because it is the reason a hydroponic grower has to think about the full nutrient solution rather than only about water and light. Related terms follow the same pattern: aeroponics delivers that solution as a mist to bare roots, and aquaponics couples the plants to fish whose waste supplies much of the nutrient.
How do I find a plant named after a particular person?
This comes up when someone wants a plant carrying a family name, often for a memorial planting. Cultivar names are the place to look, since thousands of them are personal names.
Search the registries rather than a general web search. Daylilies, irises, roses, hostas, and clematis each have an international or national registration authority with a searchable list of every registered name, and most large nurseries let you search cultivar names directly. A name search will typically turn up several unrelated candidates: an iris, a primula, a daylily, a rose, a viola, and so on, which is what makes this worth doing rather than settling for the first hit.
Then work backward from your conditions rather than forward from the name. For a grave planting somewhere that drops to 5 degrees F or lower in winter, hardiness rules out a lot immediately. A daylily or an iris cultivar will come through that comfortably. A tender perennial such as a Ruellia, whatever its name, will not survive outdoors, and a rose will need siting and some care that a cemetery plot may not get. Check the hardiness rating of the specific cultivar with a local nursery before you buy, because a name shared with a hardy relative guarantees nothing, and confirm with the cemetery what they permit and will mow around.
