logo

Home
Bamboos
Maps
Characters
Sampling
Collecting
Literature
Collaborators
Links

Buds and Branching

Hypothesis I was proposed by McClure (1966, 1973), who regarded the multiple buds of Chusquea as all primary.  Presumably the dominant bud is homologous to the single primary bud typical of bamboos, while the two to many additional smaller subsidiary buds are derived separately from meristematic tissue of the nodal region (in the more general morphology literature these would be called supernumerary buds).  Hypothesis II was proposed by Stapleton (1997), who said that extensive loss or reduction of prophylls was consistent with condensation of a single primary axis as a pathway for the evolution of the bud complement in Chusquea.  Although the main example here is Chusquea, other taxa with multiple buds include Filgueirasia or Holttumochloa.

not every character is illustrated

Hypothesis I

B-1. Primary buds per mid-culm node: 0 = 1; 1 = 2 or more; 2 = none.

B-2. Multiple primary buds, relative size: 0 = all buds subequal; 1 = central primary bud at least 2 times the diameter of the other primary buds (i.e., subsidiary buds). [Inapplicable for taxa with a single primary bud or with no buds.]

B-3. Central (or sole) primary bud shape: 0 = triangular; 1 = circular (dome-shaped).

B-4. Central (or sole) primary bud prophyll: 0 = prophyll unitary, margins free (open); 1 = prophyll unitary, margins fused (closed); 2 = prophyll binary (divided), margins free (open).

B-5. Compression of the proximal internodes of the axis developing from the central (or sole) primary bud: 0 = no compressed internodes present; 1 = one compressed proximal internode present at the very base; 2 = two to several compressed proximal internodes at the base; 3 = all internodes compressed.

B-6. Relative sizes of secondary branches developing from the central (or sole) primary axis: 0 = secondary axes subequal to the central (or sole) primary axis; 1 = at least some of the secondary axes no more than one-half the diameter of the central (or sole) primary axis.

B-7. Central (or sole) primary branch size relative to the main culm: 0 = more or less equal in diameter; 1 = smaller in diameter than the main culm.

Hypothesis II

B-8. Primary bud prophyll:  0 = present; 1 = absent. 

B-9. Primary bud shape:  0 = triangular; 1 = circular (dome-shaped).  [Inapplicable for taxa with multiple buds, unless one wishes to assume that the shape of the central bud reflects the shape of the primary bud.]

B-10. Primary bud prophyll:  0 = prophyll unitary, margins free (open); 1 = prophyll unitary, margins fused (closed); 2 = binary (divided), margins free (open).  [Again, inapplicable for Chusquea and other taxa with multiple buds.]

B-11. Compression of the proximal internodes of the primary axis:  0 = no compressed internodes present; 1 = one compressed proximal internode present at the very base; 2 = two to several compressed proximal internodes at the base; 3 = all internodes compressed. 

B-12. Relative sizes of secondary branches developing from the primary axis: 0 = secondary axes subequal to the primary axis; 1 = at least some of the secondary axes no more than one-half the diameter of the central axis.  [Under this hypothesis, the secondary branches include both the ones flanking the dominant bud/branch in Chusquea and the ones that grow from the nodes of the dominant branch once it develops.]

B-13. Primary axis size relative to the main culm: 0 = more or less equal in diameter; 1 = primary axis smaller in diameter than the main culm.

General

B-14.  Branching pattern:  0 = intravaginal; 1 = extravaginal; 2 = infravaginal. 

B-15. Thorns developing from the primary axis (or central primary axis): 0 = absent; 1 = present.

B-16. Thorn morphology: 0 = relatively short, stout, stiff and usually curved; 1 = relatively elongated, slender, more or less flexible and at most slightly curved. 

B-17. Bud/branch complement base: 0 = indistinguishable from the adjacent nodal region (promontory absent); 1 = swollen, forming a promontory that bears the bud/branch complement.

Life Span and Rhizomes
Culms
Buds and Branching
Culm Leaves
Foliage Leaves
Synflorescences
Spikelets
Flowers and Fruits
Leaf Anatomy
Leaf Micromorphology


B-1, click for larger image


B-2, click for larger image

B-3, click for larger image

B-4, click for larger image

B-5, click for larger image

B-6, click for larger image

B-7, click for larger image

B-9, click for larger image

B-10, click for larger image

B-11, click for larger image

B-12, click for larger image

B-13, click for larger image

B-14, click for larger image

B-15, click for larger image

B-16, click for larger image

B-17, click for larger image

Home - Bamboos - Maps - Characters - Sampling - Collecting - Literature - Links

Contact - Dr. Lynn Clark   Copyright © 2005-2006, Iowa State University. All rights reserved.