1. Inflorescences, Fruits and Seeds
So many, many terms…
So little time…

2. Inflorescence
An inflorescence can be defined as the shoot system which serves for the formation of flowers and which is modified accordingly.
The inflorescence form and position is important in routine identification as well as in the determination of phylogenetic relationships.

3. Inflorescence Types
Two quite different inflorescence types occur in angiosperms. These are:
Determinate (monotelic) inflorescences
Indeterminate (polytelic) inflorescences

4. Determinate Inflorescence
The main axis of the inflorescence ends in a flower.
The flowering sequence of a determinate inflorescence usually begins with the terminal flower at the top of the cluster.
Determinate inflorescences are generally ancestral to indeterminate ones.

5. Indeterminate Florescence
The growing point produces only lateral flowers or partial inflorescences (groups of flowers).
The flowering sequence usually starts at the base (or outside) of the cluster.

6. Diagramatic Representation

7. Determinate Inflorescenses
The circles represent flowers and their sequence of opening (from large to small).

8. Determinate Inflorescences
Cymes are one of the most common types of determinate inflorescences.
The lateral branches of cymes are composed of usually numerous, three-flowered units usually showing opposite branching.

9. Types of Cymes

10. Some Common Kinds of Indeterminate Inflorescences
The circles indicate flowers; their size indicates the sequence of opening (from large to small).

11. Racemes and Spikes Indeterminate Inflorescence
A raceme is an inflorescence with a single axis bearing flowers with pedicels.
A spike is similar to a raceme but the flowers are sessile (lacking a pedicel or stalk).

12. Raceme Example

13. Spike Example

14. Corymbs and Panicles Indeterminate Inflorescence
A corymb is a raceme with the pedicels of the lowermost flowers elongated, bringing all of the flowers to the approximate same level
A panicle is merely a compound raceme, that has two or more orders of branches, with each axis bearing flowers or higher-order axes.

15. Corymb Example

16. Panicle Example

17. Head or capitulum
A head (or capitulum) is a dense terminal cluster of sessile flowers.
In a determinate head, the central flowers open first.
In an indeterminate head, the peripheral (outermost) flowers open first.

18. Helianthus annuus

19. Umbel
An umbel is an inflorescence in which all of the flowers often have pedicels of approximately equal length that arise from a single region at the apex of the inflorescence axis.
Umbels are determinate if the flowers open from the center first and then proceed to the periphery.
Umbels are indeterminate if the flowers open from the periphery first and then proceed to the center.

20. Umbel Example

21. Umbel Example II

22. More on inflorescences
Simple inflorescences have only a single axis (one order of branching).
Compound inflorescences have two or more orders of branching.

23. Catkin or Ament
Any elongated inflorescence composed of numerous inconspicuous, usually wind pollinated flowers. Willows have catkins.

24. Epiphyllous Flowers
Some flowers are borne on leaves.

25. Cauliflorous Flowers
Some flowers are borne on older stems or trunks.

26. Tendrils
Inflorescences are sometimes modified for climbing by becoming elongated and twining or developing adhesive pads, thus forming tendrils.

27. Fruit
A fruit is a matured ovary along with fused accessory structures (hypanthium or perianth parts).
There is great diversity of size, form, texture, means of opening, and anatomy among fruits.
Many structures that a botanist considers to be fruits are neither sweet nor good to eat!
Seed dispersal is the primary function of fruits.

28. Parts of the Fruit

29. Pericarp aka ovary wall
In some fruits, the pericarp becomes very juicy as it matures. Often, such a fruit has a high sugar content and is readily consumed by animals.
The pericarp in many other plants dries as it matures.

30. Pericarp
Often, the pericarp is dehiscent, splitting open and releasing the seeds that it contains.
In other plants, the fruit is indehiscent; the seeds remain enclosed within pericarp tissue.

31. Pericarp
The pericarp is often differentiated into layers, particularly in fleshy fruits.
The exocarp is the outer skinlike layer.
The mesocarp is the middle layer that often becomes soft and fleshy.
Only certain kinds of fruit have a third layer, the endocarp. This innermost layer closely surrounds the seed or seeds. (ie hard pit of olive or papery apple core).
A tomato is a fleshy fruit that does not have endocarp.

32. Simple Fruits Simple fruits result from a single flower.
Simple fruits are divided into 2 categories.
1) Those formed from a single carpel or several fused carpels.
2) Those formed from several separate carpels of a single gynoecium (aggregate fruits).

33. Common Types of Simple Fruit
Fruit fleshy at maturity:
Berry – entire pericarp soft; generally with two or more seeds. Derived from either superior or inferior ovaries. Examples: tomato, banana, and grape. Includes the pome, the pepo, and the hesperidium.

34. Fruit Types associated with Berries
Pome – Derived from an inferior ovary and surrounded by a fleshy hypanthium. Restricted to the Rosaceae subfamily Maloideae. Examples: pear, apple, and quince.
Pepo – Derived from an inferior ovary with a leathery rind. Generally restricted to Cucurbiaceae family (watermelon, pumpkin, cucumber).
Hesperidium – Derived from a superior ovary with a leather pericarp having oil glands. The carpels are easily separated as segments that are lined with fleshy hairs. Restricted to Citrus and its close relatives (Rutaceae). Oranges, lemons, grapefruit.

35. Common Types of Simple Fruit
Fruits fleshy at maturity.
Drupe – Pericarp distinguishable as three layers: exocarp, mesocarp, and endocarp. The endocarp is a ‘stone’ that encloses the seed. Examples: peach, plum, cherry, coconut, olive.

36. Common Types of Simple Fruit
Fruit dry, one-seeded, not breaking apart at maturity.
Achene – Extremely variable in form. Seed and pericarp attached only by the funiculus (ovule stalk). Examples: buttercup, buckwheat. Includes also samara, cysella, and utricle.

37. Samara – A winged achene. Examples are elm, ash, and birch.
Cypsella – An achene with adnate calyx (pappus) Examples: members of the Asteraceae family such as the dandelion.
Utricle – A bladdery achene with the wall loosely surrounding the seed. Example: pigweed.

38. Common Types of Simple Fruit
Fruit dry, one-seeded, not breaking apart at maturity.
Caryopsis – Seed coat and pericarp completely adnate. Restricted to Poaceae family. Examples: maize, wheat, rye, barely, sorghum.

39. Common Types of Simple Fruit
Fruit dry, one-seeded, not breaking apart at maturity.
Nut - Exocarp hard; the fruit often subtended by an involucre (whorl of bracts). Derived from a syncarpous synoecium, but one-seeded by abortion of ovules. Examples: acorn, filbert.

40. Common Types of Simple Fruit
Fruit fleshy or dry, at maturity breaking into one- or a few-seeded segments, the seeds remain completely surrounded by the pericarp.
Schizocarp – Fruit breaking into one-carpellate segments (mericarps). Examples: members of the Apiaceae such as fennel and dill, and others such as hollyhock. Schizocarps may be winged (samaroid schizocarps) as in maple or fleshy as in madder.

41. Common Types of Simple Fruit
Fruit fleshy or dry, at maturity breaking into one- or a few-seeded segments, the seeds remain completely surrounded by the pericarp.
Nutlet – Friut deeply four-lobed, breaking into one-seeded half-carpellate segments; used especially for fruits of borage, vervain, and mint families. Examples: sage, borage.

42. Common Types of Simple Fruit
Fruit dry at maturity dehiscing either lengthwise, or by pores, teeth or a lid and exposing the seeds.
Capsule – Syncarpous and typically several- to many-seeded. Perhaps the most common and certainly the most variable of dehiscent fruits.

43. Septicidal capsule – Opens lengthwise along the septa
Septicidal capsule – Opens lengthwise along the septa. Example: zigadene.
Loculicidal capsule – Opens lengthwise between the septa and directly into the locule (evening primrose and iris).
Poricidal capsule – Opens by pores near the top (poppy)

45. Schizocarpic capsule – Breaks completely apart at the septa into one-seeded segments (castor bean).
Denticidal capsule – Opens apically by a ring of teeth (Eucalyptus, chickweed)
Circumscissile capsule – Opens horizontally in a ring so that a lid is formed (purslane, plantain, portulaca)

47. Common Types of Simple Fruit
Fruit dry at maturity dehiscing either lengthwise, or by pores, teeth or a lid and exposing the seeds.
Silique – A long, narrow (more than twice as long as broad) 2-carpellate fruit whose outer walls break away from a central papery partition. Restricted to Brassicaceae. Examples mustard, kale.

48. Silique

49. Common Types of Simple Fruit
Fruit dry at maturity dehiscing either lengthwise, or by pores, teeth or a lid and exposing the seeds.
Follicle – Unicarpellate, dehiscing along one suture (Examples: milkweed, larkspur).

50. Milkweed Follicle

51. Common Types of Simple Fruit
Fruit dry at maturity dehiscing either lengthwise, or by pores, teeth or a lid and exposing the seeds.
Legume – Unicarpellate, dehiscing along two sutures. Restricted to the Fabaceae. Examples: Bean and pea.

52. Simple Fruit Derived from more than one ovary.
Fruit derived from a flower with an apocarpous gynoecium.
Aggregate – The ovary of each carpel matures into one of the simple fruits described previously. A raspberry is an aggregate of small drupes.

53. Simple Fruit Derived from more than one ovary.
Fruit derived from a flower with an apocarpous gynoecium.
Accessory – Tissue other than or in addition to the ovary enlarges and becomes fleshy. Examples: strawberry and blackberry in which the receptacle becomes fleshy.

54. Simple Fruit Derived from more than one ovary.
Fruit derived from a flower with an apocarpous gynoecium.
Hip – The hypanthium of a perigynous flower enlarges and becomes fleshy at maturity but does not become adherent to the carpels. Known only from certain Rosaceae, especially Rosa. The ovaries usually mature into achenes.

55. Simple Fruit Derived from more than one ovary.
Fruit derived from a flower with an apocarpous gynoecium.

56. Multiple Fruit
A multiple fruit is the product of the gynoecia of several closely clustered flowers.
The individual ovaries of each flower develop into one of the simple fruits described previously. Accessory tissue such as the calyx of the mulberry or the inflorescence axis of the pineapple may become fleshy. The fruit appears to be ‘merged’ together.
The synconium is a special kind of multiple fruit restricted to Ficus (fig) where the inflorescence axis enlarges and surrounds the flowers and becomes fleshy. The individual ovaries mature as achenes.

57. Seed
A seed is a matured ovule that contains an embryo and often its nutritive tissues (endosperm, perisperm).
The seed is surrounded by a seed coat.
Seeds may be variously sized and shaped. They may be associated with a wing or tuft of hairs.

58. Endosperm
Endosperm is a usually triploid tissue derived from the union of the two nuclei in the central cell of the female gametophyte. Endosperm may be homogeneous (uniform in texture) or ruminate (dissected by partitions that grow inward from the seed coat).
Endosperm may contain starch, oils, proteins, oligosaccharides, and/or hemicellulose.
Endosperm may be hard to soft and fleshy.

59. Perisperm
Perisperm is a specialized diploid nutritive tissue derived from the megasporangium.

60. Seed Coat
The testa (plural testae) of a seed coat develops from the outer integument.
The tegmen (plural tegmina) of a seed coat develops from the inner integument.
The testa varies in surface texture due to the pattern and outgrowths of the individual cells composing its surface.
The testa is sometimes colorful and fleshy.

61. More on Seeds
Some seeds are associated with a hard to soft, oily to fleshy, and often brightly colored structre called an aril.
An aril is usually an outgrowth of the funiculus or the outer integument.
The seed bears a scar called the hilum (plural hila) at the point where it was attached to the funiculus.

62. Seed Embryo
The embryo consists of an epicotyl, a radicle, a hypocotyl, and usually one or two cotyledons (seedling leaves).

63. Seed Embryos Continued
The epicotyl develops into the shoot.
The radicle develops into the primary root and usually gives rise to the root system.
The hypocotyl connects the epicotyl and radicle.
The cotyledons (seedling leaves) may be leaflike, fleshy, or modified as nutrient-absorptive structures.