(characters in this key will be linked to further illustrations, along with those in the morphology components section)
Key to genera of bamboos cultivated in Europe & the US from vegetative characters
1a. Rhizomes pachymorph, having root-bearing internodes thicker than the culm; culms usually in single clumps.
2a. Tropical to subtropical bamboos (1--)5--30 m; mid-culm branches initially 3(--9); mid-culm culm sheath blades broad, length usually less than twice width, or maximum breadth similar to rest of sheath; leaf blades with minor veins parallel.
3a. Mid-culm branches initially ca. 3(--7), dissimilar, central often strongly dominant.
4a. Culms dense to loose, 1--20 m; leaf blades usually broad, to 10 cm wide; culm sheaths deciduous.
5a. Culms usually lightly waxy at first; basal branching usually well developed
5b. Culms usually with dark or thick waxy scurf at first; basal branching usually absent or restricted.
6a. Culms sheaths very broad, base encircling culm without substantial overlap, pubescence dense and soft; culms often striped
6b. Culms sheaths narrow to broad, base encircling culm without substantial overlap, pubescence varied; culms not striped
4b. Culms very dense, ca. 5--15 m; leaf blades very narrow, less than 2 cm wide, culm sheaths persistent
3b. Mid-culm branches initially 5--9, subequal
2b. Temperate to subtropical bamboos 3--12 m tall; culm sheath blades narrow, length more than twice width; mid-culm branches initially 5--9(--100); leaf blades with minor leaf veins parallel or tessellate.
7a. Mid-culm branches initially 20--100; culm internodes solid
7b. Mid-culm branches initially 3--20; culm internodes hollow.
8a. Branches initially 3-5; some lower nodes with prominent thorns or bumps
8b. Branches initially 5-20; lower nodes without thorns or bumps.
9a. Leaf blades with minor veins all parallel.
10a. Culm sheath interior surface distally scabrous; branches initially ca. 20--30, subequal
10b. Culm sheath interior surface glabrous; branches initially ca. 10--20, central dominant
9b. Leaf blades with prominent tessellation of minor veins.
11a. Mid-culm branches initially ca. 5; culm sheath blade erect, contiguous with sheath apex; mid-culm buds with 2 initials visible inside
11b. Mid-culm branches initially (5--)7--10; culm sheath blade erect or reflexed, articulated with sheath; mid-culm buds with more than 2 initials visible inside.
12a. Rhizomes consistently long-necked or short and long-necked, spreading bamboos with culms solitary or in several clumps
13a. Nodes raised, basal culm nodes usually with thorns
12b. Rhizomes consistently short-necked, culms in a single clump.
14a. Culms usually finely ridged, wax persistent
14b. Culms usually smooth, wax absent or deciduous
15a. Culm sheaths deciduous, leaf blade orientation regular
16a. Leaf blade tessellation strong, leaf blade orientation irregular
16b. Leaf blade tessellation weak, leaf blade orientation regular
1b. Rhizomes leptomorph, root-bearing internodes thinner than the culm; culms solitary or in many connected clumps.
16a. Mid-culm branches consistently 2, unequal, rarely with a smaller central third branch
16b. Mid-culm branches not consistently 2, initially 1--9.
17a. Mid-culm branches 4--5, less than 10 cm long, without any further branching; leaves usually solitary
17b. Mid-culm branches to more than 10 cm long, often branching further, leaves in groups.
18a. Culm sheath blade narrow and very small, less than 1 cm; culms often quadrangular; nodes often swollen, brittle, often with thorns; culm bud prophyll very narrow or absent; mid-culm branches initially 3(--5)
18b. Culm sheath blade broad or more than 1 cm; culms not quadrangular; nodes slightly swollen or level, not brittle, without thorns; culm bud prophyll broad; mid-culm branches initially 1--9.
19a. Dwarf bamboos, less than 1(--1.5) m tall.
20a. Leaf blade margins more or less bleached in winter, terminal blade often angled from shoot axis, blades usually not variegated
20b. Leaf blade margins not or only slightly bleached in winter, terminal blade parallel to shoot axis, blades often variegated
19b. Medium-stature to tall bamboo, more than 1 m tall.
21a. Mid-culm branches initially 5--9.
22a. Culm buds initially closed
22b. Culm buds initially open.
21b. Mid-culm branches initially 1--3(--5).
24a. Mid-culm branches 1(--3); branch and leaves often very large relative to culm size.
25a. Leaf blade margins bleached in winter, terminal blade often deflexed from shoot axis; culm buds initially closed; mid-culm branch 1
25b. Leaf blade margins not bleached in winter, terminal blade parallel to shoot axis; culm buds initially open or closed; mid-culm branches 1(--3)
26a. Culm buds usually initially open; mid-culm branches 1(--3); culm internodes usually distally yellow-brown scurfy
26b. Culm buds all initially closed; mid-culm branch 1; culm internodes glabrous
..... Pseudosasa subgen. Pseudosasa
24b. Mid-culm branches (1--)2--7; branches and leaves small to medium relative to culm size.
27a. Mid-culm branches consistently 3; culm buds initially closed.
28a. Central branch somewhat larger, branches spreading; supra-nodal ridge prominent
28b. Branches subequal, erect; supra-nodal ridge obscure
..... Pseudosasa subgen. Sinicae
27b. Mid-culm branches 2--7; culm buds initially open.
29a. Leaf blades smooth, well separated; culm sheaths late-deciduous; native to Himalayas & s w China
29b. Leaf blades ribbed, closely spaced; culm sheaths very persistent; indigenous to SE USA