by Bob Harms 

B. trifoliolata 1 month 4 months

B. swaseyi - 3 years

The cotyledons and first true (juvenile stage 1) leaves do not differentiate our Berberis species, nor the hybrids. Cotyledons are narrowly oblong with rounded emarginate tips. The first true leaves develop late in the first full season from the first node between the cotyledons. These are pedicellate, simple, suborbicular, palmately veined, often with a notched truncate base and with 7-13 marginal spines. Trifoliate and multileaflet adult leaves do not generally form until the second season or even much later — especially with B. swaseyi.

As we see above the 4-month B. trifoliolata (in December) even exhibits the 'maroon shift' typical of B. swaseyi. The 3-year B. swaseyi plant (also December) has both juvenile and adult leaves.

In all some five stages of leaf morphology are noted for our Berberis (with images all from B. trifoliolata):

Stage 1 leaves on 5 cm. stem with many seasons of budscales/scars.

1. Stage 1: All seedlings. Suborbicular simple leaves with a truncate base, often notched — the notch generally becoming more pronounced with age. Venation also shifts gradually from palmate to 1-veined from the base. Stage 1 leaves are often produced for many years. With older seedlings of B. trifoliolata (and hybrids) these leaves become triangular; with B. swaseyi they remain rounded.
   

   Stage 1 & Stage 2 leaves	Notched base of Stage 1 leaf

2. Stage 2: Common among juveniles. Asymmetrical bifoliolate leaves, with the notched base of stage 1 now separating the two leaflets. Rarely found with older plants, but have been found with plants c. 1 meter high.
3. Stage 3: Uncommon juvenile form noted with B. trifoliolata. Symmetrical trifoliate leaves with significantly reduced lateral leaflets. These closely resemble the reduced basal leaflets of B. swaseyi. One B. swaseyi exhibited a similar 3-foliate leaf, however with a stalked terminal leaflet.
   

   Stage 3 leaf	Leaves at stages 4, 2 & 1

4. Stage 4: As with stage 3, but with more or less equal leaflets (if trifoliate), but all quite broad in comparison with adult more elongated leaflets. B. swaseyi had both stalked and unstalked terminal leaflets, as well as 3– and 5–foliolate leaves, the lower pair reduced.
5. 
   

   Adult trifoliate leaves.