Let me share with you a difference between lycopsida and sphenopsida.
| Aspect | Lycopsida | Sphenopsida |
| Common name | Clubmosses | Horsetails |
| Stem | Branched, often dichotomously | Jointed, with distinct nodes and internodes |
| Leaves | Microphylls or small leaves with a single unbranched vein | Reduced, scale-like leaves arranged in whorls at nodes |
| Vascular Tissues | Protoxylem and metaxylem, with more complex vascular tissue arrangement | Hollow internodes with a central cavity, strengthened by silica deposits |
| Reproductive Structures | Strobili (cone-like structures) often complex with sporophylls arranged in whorls | Cone-like structures with sporangia borne on sporophylls |
| Roots | True roots present, emerging from the rhizome | Rhizomes with reduced roots and often rhizoids |
| Sporangia | Sporangia borne on the lower surface of specialized sporophylls | Sporangia often aggregated into cones or strobili |
| Homosporous or Heterosporous | Mostly homosporous (produce one type of spore) | Homosporous but some extinct species were heterosporous |
| Silica deposits | Generally lack silica deposits in the stem | Contain silica deposits in the stem for added structural support |
| Leaf Whorls | Leaves not arranged in distinct whorls | Leaves arranged in distinct whorls at nodes |
| Examples | · Lycopodium · Selaginella · Isoetes | · Equisetum, · Calamites (extinct) |