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Morphological and Developmental Characters

Morphological and Developmental Characters for Hornworts

Vegetative

1. Apical cell morphology: wedge-shaped (0); hemidiscoid (1); other (2)
2. Thallus: ecostate (0); costate (1)..
3. Habitat; on soil or rock (0); epiphytic (1).
4. Nostoc symbionts: absent (0); present (1).
5. Stoma-like clefts on gametophyte: absent (0); present (1).
6. Location of stoma-like clefts: ventral side (0); both ventral and dorsal sides (1).
7. Slime papillae or hairs on gametophyte: present (0); absent (1).
8. Thallus: solid (0); cavernous (1).
9. Thallus cell trigones: absent (0); present (1).
10. Epidermal cells: similar to internal cell (0); smaller than (1).
11. Tubers: absent (0); present (1).
12. Gemmae: absent (0); present (1).
13. Ability to distinguish D-methionine: absent (0); present (1).
14. Ability to biosynthesize megacerotonic acid; absent (0); present (1).
15. Ability to biosynthesize rosmarinic acid; absent (0); present (1).

Chloroplast

16. Monoplastidic meristematic cells: present (0); absent (1)
17. Chloroplast number per cell: one (0); more than (1).
18. Axial microtubule system: absent (0); present (1).
19. Pyrenoid subunits: irregular (0); irregular with inclusions (1); lens-shaped (2); absent
20. Grana end membranes: absent (1); present (2).
21. Channel thylakoids: absent (0); present (1).
22. Plastoglobuli: absent (0); present (1).

Gametangia

23. Archegonium: stalked (0); embedded in thallus (1).
24. Number of cell rows in archegonial neck: four (0); five (1); six (2).
25. Antheridium: exogenously (0); endogenously (1).
26. Number of antheridia per cavity: one (0); two-four (1); numerous (2).
27. Spermatozoid: asymmetric (0); bilaterally symmetric (1).
28. Jacket of antheridium: irregularly arranged small cells (0); four-tiers of cells (1).
29. Origin of centrioles: always present (0); in spermatogenous tissue (1); in spermatid mother cell (2).
30. Coiling of sperm: uncoiled (0), coiled left (1); coiled right (2).

Embryo and Fertilization

31. Thallus growth after fertilization: present (0); absent (1).
32. First division of zygote: transverse (0); vertical (1).

General sporophyte

33. Capsule position: erect (0); horizontal (1).
34. Capsule: projecting from involucre (0); enclosed by involucre (1); involucre absent (2).
35. Meristematic activity: limited (0); persisting (1).
36. Sporogenous cells: derived from endothecium (0); from amphithecium (1).
37. Synchronous spore production: present (0); absent (1).
38. Dehiscence of sporophyte: irregularly or indehiscent (0); ruptured into two valves (1).
39. Thickenings in capsule walls: longitudinal (0); transverse (1); absent (2).
40. Suture lines in sporophyte: present (0); absent (1).
41. Columella: absent (0); poorly developed (1); well-developed (2).
42. Sporophyte stomata: absent (0); present (1); reduced to pores (2).

Involucre

43. Involucre length: 2.5-5mm (0); 1-2.5mm (1); 5-10mm (2).
44. Involucre surface; smooth (0); crenulate or lamellate (1).

Spores

45. Spore mother cell lobed: present (0); absent (1).68. Callose in sporocyte wall: present (0); absent (1).
46. Monoplastidic spore mother cell: present (0); absent (1).
47. Perine in spore wall: absent (0); present (1).
48. Spore wall exine: nontripartite (0); tripartite lamellae (1).
49. Spore-tetrad: tetrahedral (0); bilateral (1); tetrahedral with indistinct trilete mark (2).
50. Spore shape: globose to tetrahedral (0); ovoid to kidney shaped (1); irregular (2).
51. Spore equatorial girdle (cingulum): absent (0); present (1).
52. Spore surface: ornamented (0); smooth (1); canaliculate-striate (2).
53. Spore size; medium to large (0); extremely small (less than 22mm) (1).
54. Spore germination: exosporic (0); endosporic (1).
55. Spore color; green (0); yellow (1); dark brown to black (2).

Pseudoelaters

56. Pseudoelater: unicellular (0); multicellular (1).
57. Pseudoelaters spiraled thickening: absent (0); present (1); weak oblique thickenings (2).
58. Pseudoelaters: thin-walled (0); strongly thick-walled (1).
59. Pseudoelater autofluorescent; present (0); absent (1).
60. Pseudoelater color: brown (reddish) (0); yellow or light brown (1).
61. Pseudoelater apex: obtuse (0); acute (1).

Foot and Placenta

62. Foot shape: long-tapering (0); bulbous (1); conical-slightly elongate (2); ovoid (3); cup-shaped (4); spheroidal (5)
63. Palisade layer in foot: absent (0); present (1).
64. Transfer cells: gametophyte (0); gametophyte and sporophyte (1); sporophyte (2); absent (3).
65. Transfer cells labyrinthine: simple (0); complex (1).
66. Placental protein crystals: absent (0); present (1).
67. Timing of placental transfer cells: early (0); late (1); continuous (2).

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