1	"Plants with evident above-ground stems, these varying from decumbent to ascending or  vertical, if decumbent, sometimes forming large clumps"	2
1	"Plants without evident above-ground stems, sometimes suckering and forming dense clusters"	28
2	"Inflorescences usually simple (very occasionally with 1-2 branches in A. lindenii)"	3
2	"Inflorescences branched"	6
3	"Leaves up to 6 cm long"	"Aloe jucunda"
3	"Leaves 10-90 cm long"	4
4	"Leaves 60-90 cm long; flowers greenish yellow or white"	"Aloe orlandi"
4	"Leaves 10--45 cm long; flowers various shades of pink or red"	5
5	"Leaves 10-12 cm long; inflorescence up to 40 cm tall; perianths about 24 mm long"	"Aloe hemmingii"
5	"Leaves 40-45 cm long; inflorescences up to 70 cm tall; perianths about 30 mm long"	"Aloe lindenii"
6	"Inflorescences to 45 cm tall"	7
6	"Inflorescences 60-150 cm tall"	10
7	"Plants acaulescent; perianths 30-35 mm long"	"Aloe rubrodonta"
7	"Plants caulescent, the stems weak, decumbent or becoming so; perianths 10-28 mm long"	8
8	"Leaf margins with brown-tipped teeth about 4 mm long"	"Aloe heybensis"
8	"Leaf margins entire or with white teeth about 0.5 mm long near the tips"	9
9	"Leaf exudate dark orange-brown when fresh, drying brown; leaves olive green; stems to 55 cm long"	"Aloe kahinii"
9	"Leaf exudate clear both when fresh and when dry; leaves dull brownish; stems 15-20 cm long"	"Aloe luntii"
10	"Perianth with a pronounced basal swelling"	11
10	"Perianth without a pronounced basal swelling"	12
11	"Leaves spotted; flowers orange"	"Aloe grisea"
11	"Leaves striate; flowers dull pink"	"Aloe albovestita"
12	"Leaves with marginal teeth 4-6 mm long; perianths red"	"Aloe sanguinalis"
12	"Leaves with marginal teeth to 1.5 mm long; perianths orange or dull pink"	13
13	"Leaves shiny, white-spotted; perianth glabrous"	14
13	"Leaves not shiny, usually unspotted; perianth sometimes pubescent"	16
14	"Perianth yellow; bracts 10-12 mm long"	"Aloe peckii"
14	"Perianth red; bracts 5-8 mm long"	15
15	"Leaves 20-40 cm long, rigid, bright green; inflorescence less than 90 cm tall"	"Aloe somaliensis"
15	"Leaves 40-50 cm long, leathery, grey or brownish-green; inflorescence more than 100 cm tall"	"Aloe parvidens"
16	"Leaves rugose"	"Aloe scobinifolia"
16	"Leaves smooth"	17
17	"Inflorescences panicles with many spreading branches"	18
17	"Inflorescences with up to 10 ascending branches"	21
18	"Leaves ascending to erect; marginal teeth many, white, about 0.5 mm long"	"Aloe ruspoliana"
18	"Leaves spreading to recurved; marginal teeth various"	19
19	"Leaves shorter than 50 cm; margins entire, sinuous, or with minute teeth the same color as the margin"	"Aloe brunneostriata"
19	"Leaves 50-70 cm long; margins with distinct, hard, brown teeth"	20
20	"Leaf margins with teeth 1-2 mm long; panicle branches oblique, much elongated, rather lax; perianth about 23 mm long"	"Aloe microdonta"
20	"Leaf margins with teeth 5-6 mm long; panicle branches erect, subdense, cylindrical-conical; perianth 28-30 mm long"	"Aloe megalacantha"
21	"Perianth pubescent to tomentose"	22
21	"Perianth glabrous"	25
22	"Perianth densely tomentose"	"Aloe molederana"
22	"Perianth pubescent"	23
23	"Leaves white-spotted, erect; marginal teeth about 1.5 mm long"	"Aloe citrina"
23	"Leaves unspotted; marginal teeth about 1-6 mm long"	24
24	"Leaves green, erect, 60-80 cm long; marginal teeth 4-6 mm long"	"Aloe rigens"
24	"Leaves glaucous-green with reddish tinge, ascending to spreading, 40-50 cm long; marginal teeth about 1-3 mm long"	"Aloe glabrescens"
25	"Leaves with dark green lines"	"Aloe bargalensis"
25	"Leaves uniformly colored or with a few white spots"	26
26	"Leaves bright green with a few white spots, up to 70 cm long"	"Aloe officinalis"
26	"Leaves uniformly colored, grey-green or pinkish brown, less than 50 cm long"	27
27	"Leaves pinkish brown, about 50 cm long; panicle branches densely flowered, capitate"	"Aloe bella"
27	"Leaves glaucous green with reddish tinge, 30-35 cm long; branches lax, cylindrical"	"Aloe breviscapa"
28	"Inflorescences simple"	29
28	"Inflorescences branched"	30
29	"Leaves lanceolate, unspotted; marginal teeth robust; inflorescence rather dense"	"Aloe cremnophila"
29	"Leaves linear-lanceolate, copiously spotted; marginal teeth small; inflorescence lax"	"Aloe gillettii"
30	"Plants to 50 cm tall"	31
30	"Plants taller than 75 cm, shrubby or treelike; leaves longer than 20 cm and more than 3 cm wide"	32
31	"Leaves to 50 cm long, drooping; inflorescence to 50 cm long, drooping but branches ascending"	"Aloe nugalensis"
31	"Leaves to 20 cm long, unspotted; inflorescence to 100 cm long, ascending to erect, branches spreading"	"Aloe ambigens"
32	"Plants densely shrubby, many stemmed; inflorescence branches capitate, subglobose"	"Aloe rabaiensis"
32	"Plants few-stemmed or with only one stem; branches cylindrical or conical, rather lax"	33
33	"Plants trees, branching from a central stem and having a crown"	34
33	"Plants with a lax, shrubby growth habit"	35
34	"Perianths pale yellow with greenish tips; inflorescences with 7-18 branches, flowers not crowded on the branches"	"Aloe miskatana"
34	"Perianths red; inflorescences with 2-5 branches, flowers somewhat crowded on the branches"	"Aloe eminens"
35	"Stems shorter than 100 cm, decumbent or erect; leaves with sinuate-dentate margins; teeth 2-3 mm long, pungent"	36
35	"Stems more than 100 cm tall, always erect; leaves with straight white margins; teeth up to 1 mm long, white, rather soft"	37
36	"Stems decumbent to ascending; leaves green; teeth reddish brown; perianth 26-30 mm long"	"Aloe hildebrandtii"
36	"Stems stout, erect; leaves glaucous with reddish-violet tinge; teeth white; perianth 20-22 mm long"	"Aloe heliderana"
37	"Stems less than 150 cm tall; bracts about 5 mm long"	"Aloe retrospiciens"
37	"Stems to 200 cm tall or more; bracts 2-3 mm long"	38
38	"Stems 200-400 cm tal; leaves 5-60 cm long and about 8 cm wide, grooved on upper surface; perianth yellow, outer tepals free for about 12 mm"	"Aloe gracilicaulis"
38	"Stems up to 200 cm tall; leaves to 30 cm long, 5-6 cm wide, flat or convex on upper surface; perianth red, outer tepals free for 5-6 mm"	"Aloe medishiana"