Bulbophyllum sect. Umbellata in Flora of China @ efloras.org

12. Bulbophyllum sect. Umbellata Bentham & J. D. Hooker, Gen. Pl. 3: 503. 1883.
伞形组 san xing zu

Rhizome creeping or straggling; roots sprouting mainly below pseudobulbs, spreading; new shoots arising from basal node of pseudobulb. Pseudobulbs distinct, apex with 1 leaf. Leaves persistent, thick. Inflorescence solitary, arising near pseudobulbs, a ± subumbellate raceme. Pedicel with basal node ± coinciding with attachment of subtending bract. Sepals: margins glabrous, 3-7-veined; lateral sepals usually longer than dorsal sepal, twisted inward near base, upper margins approaching or meeting and connate (free and not twisted in Bulbophyllum violaceolabellum). Petals: margins glabrous, 1-5-veined; lip: margins without auricles or lateral lobes, margins otherwise ± glabrous (ciliolate in B. unciniferum), adaxially ± glabrous. Column: stigma not protruding at its base, foot distinct; anther: front margin projecting or not, abaxially with or without a low, rounded crest; pollinia 4, inner 1/2 as long as outer or longer, all without appendages.
Thirty-eight provisionally accepted species: India to New Guinea; 19 species (five endemic) in China.

1 Dorsal sepal slightly shorter than lateral sepals. 43 B. violaceolabellum

+ Dorsal sepal 1.5-6 × shorter than lateral sepals (2)

2 (1) Lateral sepals 2.5-6 cm (3)

+ Lateral sepals less than 2.5 cm (7)

3 (2) Leaf 2.5-6.5 × 1-1.5 cm; flowers white. 44 B. caudatum

+ Leaf 8-25 × 2.2-6 cm; flowers purple, deep yellow, or yellowish white striped with reddish brown or tinged with purplish red (4)

4 (3) Stelidia distally widened, tip obtuse, erose or bidenticulate (5)

+ Stelidia distally tapering, acute (6)

5 (4) Petals truncate to emarginate and mucronate; lateral sepals ca. 60 mm. 45 B. delitescens

+ Petals rounded and mucronate; lateral sepals 25-37 mm. 46 B. macraei

6 (4) Median sepal shortly mucronate; petals truncate and mucronate, 5-7-veined. 47 B. funingense

+ Median sepal caudate with a thread ca. 3 mm; petals tapering, caudate, 3-veined. 48 B. tianguii

7 (2) Scape nearly as long as or sometimes slightly longer than pseudobulb (8)

+ Scape 3-7 × as long as pseudobulb (9)

8 (7) Rhizomes suberect or ascending; lateral sepals forming a conic tube. 49 B. unciniferum

+ Rhizomes creeping; lateral sepals forming a slipper-shaped synsepal. 50 B. spathulatum

9 (7) Lip densely hirsute on margin and abaxial surface. 62 B. gongshanense (B. "Section 13")

+ Lip margin and abaxial surface glabrous (10)

10 (9) Lip narrowed, drawn-out and somewhat thinly cylindric in apical half (11)

+ Lip not thinly cylindric in apical half (12)

11 (10) Lip hooked-revolute at apex; anther cap entire apically. 51 B. japonicum

+ Lip not hooked-revolute at apex; anther cap with comblike teeth apically. 52 B. fordii

12 (10) Lateral sepals free (13)

+ Lateral sepals adhering or connate along their upper and/or lower edges (16)

13 (12) Petals acute. 53 B. elatum

+ Petals rounded to obtuse (14)

14 (13) Column without wings along lower margins. 54 B. rolfei

+ Column with deltoid to triangular, rounded to acute wings along lower margins, near base (15)

15 (14) Column with acute wings along lower margins. 55 B. guttulatum

+ Column with rounded wings along lower margins. 56 B. umbellatum

16 (12) Pseudobulbs globose; leaves elliptic-oblong, ca. 1 cm. 57 B. sphaericum

+ Pseudobulbs ovoid-conic to narrowly ovoid; leaves oblong or ovate-lanceolate, 1.6-8 cm (17)

17 (16) Lateral sepals papillose abaxially (18)

+ Lateral sepals glabrous (19)

18 (17) Lateral sepals ca. 7 mm; scape ca. 2 cm. 58 B. bomiense

+ Lateral sepals 14-27 mm; scape 3-7 cm. 59 B. farreri

19 (17) Lateral sepals 11-21 mm; flowers yellow, ± with purple-red veins or becoming reddish. 60 B. retusiusculum

+ Lateral sepals 5-10 mm; flowers deep or dark red, usually ± with deep-colored spots or veins. 61 B. tigridum