Watermelon berries (Streptopus amplexifolius) https://www.thinglink.com/card/1209572586724261895
Grows in very wet, dense undergrowth, usually with ferns and skunk cabbage.
Alternate, oblong-lanceolate leaves
Leaves are sessile
Parallel venation
Fruits (berries) hang from axils/peduncles
Axile placentation
3 carpels
Highbush cranberry (Viburnum trilobum) https://www.thinglink.com/card/1209580316885254151
Widely spread but grows abundantly in understory of mixed spruce/birch forests.
Opposite leaves, three-lobed
Serrated margins
Palmate venation
Corymb inflorescence
Fruit: drupe, flat seed
Apical placentation
Alaska Blueberry (Vaccinium ovalifolium) https://www.thinglink.com/card/1209580855794597895
Prefers acidic soil, abundant in previously logged or burned areas.
Leaves: ovate, alternating, simple
Axile placentation
5 carpels
True berry
Great, for Watermelon berries (Streptopus amplexifolius) you nicely illustrated the single locule with intruded parietal placentation, commonly we find axile placentation with multiple locules (as in Tulip), but Streptopus is different.