1	Many large intermediate veins with fibrous extensions to both adaxial (upper) and abaxial (lower) surfaces forming girders across the leaflet (Fig. 5A, 6A)	Syagrus campylospatha
–	No such girders formed	2
2	Margin of leaflet protected by a layer of thick-walled cells (Fig. 2E, 6B)	Syagrus harleyi
–	Margin of leaf lacking protective layer with few fibers, veins with exaggerated fibrous sheaths, large fibrous bundles	3
3	Margin with a huge fully functional major vein with a somewhat exaggerated fibrous sheath at or near the margin (Fig. 6C)	Syagrus procumbens“emasensis”
–	Margin with a vein with an exaggerated fibrous sheath, fiber bundles or anything other than a major vein	4
4	Minor veins adjacent to both the adaxial and abaxial surface (Fig. 6D-H)	5
–	Minor veins mostly present adjacent to the abaxial surface and few if any on the adaxial surface	9
5	A minor to intermediate vein with an exaggerated fibrous sheath adjacent to the margin and occupying less than half of the margin (Fig. 6D)	Syagrus cerqueirana
–	A major vein with an exaggerated fibrous sheath adjacent to the margin and occupying more than half to nearly the entire margin (Fig. 2A)	6
6	Marginal vein with exaggerated fibrous sheath occupies over half of the margin but not the entire margin (Fig. 6E)	Syagrus minor
–	Marginal vein with exaggerated fibrous sheath occupies the entire margin	7
7	Major vein usually unattached separated from the hypodermis by another cell layer or two (Fig. 2A, 6F)	Syagrus allagopteroides
–	Major vein usually attached to the adaxial hypodermis but separated from the abaxial by an additional cell layer or two	8
8	Minor fiber bundles along the adaxial nearly round in shape (Fig. 6G)	Syagrus lilliputiana
–	Minor fiber bundles along the adaxial elongated, longer than wide (Fig. 6H)	Syagrus cerqueirana
9	Vein with a very large exaggerated fibrous sheath adjacent to the margin	10
–	Margin without such a vein but with or without minor veins, and/or minor or major large fiber bundles	13
10	Minor veins near the middle of the mesophyll (Fig. 6J)	Syagrus longipedunculata
–	Minor veins adjacent to the lower abaxial surface	11
11	Most large adaxial fiber bundles reaching less than 1/4 to 1/5 across the mesophyll (Fig. 6I)	Syagrus loefgrenii
–	Most large adaxial fiber bundles reach 1/3 to 1/2 across the mesophyll	12
12	A few minor veins near or attached to the adaxial surface and veins often alternating with the minor fiber bundles adjacent to the abaxial surface (Fig. 6K)	Syagrus angustifolia
–	No minor veins near or attached to the adaxial surface and minor veins but no fiber bundles present on the abaxial surface (Fig. 6L)	Syagrus itacambirana
13	Large major vein near the margin but not adjacent to it (Fig. 6N)	Syagrus procumbens
–	Major veins neither near the margin nor adjacent to it	14
14	Margin with one very large fiber bundle or the first or second adaxial fiber bundles are larger than the rest	15
–	Margin with no significantly large fiber bundles	24
15	Adaxial fiber bundles long and skinny and reaching less than 1/5 to ¼ across the mesophyll (Fig. 6M)	Syagrus petraea
–	Adaxial fiber bundles long and usually fat and reaching 1/3 to 1/2 across the mesophyll	16
16	No minor fiber bundles scattered throughout the mesophyll	17
–	Minor fiber bundles scattered throughout the mesophyll	22
17	Minor fiber bundles usually absent from the abaxial surface	18
–	Minor fiber bundles usually present either along the abaxial surface and/or margin	19
18	Major veins are usually attached adaxially (Fig. 2D, 7A)	Syagrus gouveiana
–	Major veins are usually unattached (Fig. 7B)	Syagrus duartei
19	One major fiber bundle adjacent to the margin	20
–	No major fiber bundle adjacent to the margin	21
20	Minor veins all attached to the adaxial hypodermis (Fig. 2B, 7C)	Syagrus caerulescens
–	Some adaxial minor veins attached but many unattached (Fig. 7D)	Syagrus rupicola
21	Major vein attached to adaxial surface by a fibrous sheath extension (Fig. 7E)	Syagrus glazioviana
–	Major vein usually unattached (Fig. 7F)	Syagrus evansiana
22	Major veins surrounded by a very thick fibrous sheath (Fig. 7G)	Syagrus werdermanii
–	Major veins surrounded by a thin to medium fibrous sheath	22
23	Adaxial fiber bundles mostly long and skinny in cross-section (Fig. 2C, 7H)	Syagrus vagans
–	Adaxial fiber bundles mostly long and thicker (Fig. 7I)	Syagrus microphylla
24	Most adaxial fiber bundles reach less than 1/5 across the mesophyll (Fig. 7J)	Syagrus pleiocladoides
–	Most adaxial fiber bundles reach 1/3 to 1/2 across the mesophyll	25
25	Leaflets deflexed, adaxial fiber bundles more rounded (Fig. 7L)	Syagrus pleioclada
–	Leaflets straight or erect, adaxial fiber bundles long and skinny	26
26	Leaflets silvery blue color, very small minor fiber bundles between the veins and intermediate fiber bundles adaxially, and a few minor fibers abaxially (Fig. 7L)	Syagrus graminifolia
–	Leaflets green in color, no or few small minor fiber bundles between the veins and intermediate fiber bundles adaxially and none abaxially	27
27	Leaflets with many minor fibers adjacent to the margin (Fig. 7M)	Syagrus mendanhensis
–	Leaflets with one to no minor fiber bundles adjacent to the margin (Fig. 7N)	Syagrus graminifolia var. glazioviana