Tuesday, March 8, 2016

Narcissus pseudonarcissus

Narcissus pseudonarcissus (2n=14, 22, 26, with numerous aneuploid and polyploid derivatives) commonly known as Daffodil is a well-known European flower and an important ornamental crop. 
Photograph of solitary Daffodil flower.

Scientific classification
Kingdom: Plantae
Clade: Angiosperms
Clade: Monocots
Class: Equisetopsida
Subclass: Magnoliidae
Superorder: Lilianae
Order: Asparagales
Family: Amaryllidaceae
Genus: Narcissus
Species: N. pseudonarcissus

Inflorescence
Usually a solitary flower is produced at the tip of a leafless peduncle or scape, arising from basal rosette (scapose). The scape is found form an umbel with up to 20 blooms, in some Narcissus sp..

Botanical illustration of Narcissus pseudonarcissus.
Anthesis
Flowers are usually produced from March to April. Prior to opening, the flower buds are enveloped and protected in a thin dry papery or membranous (scarious) spathe. As the bud grows, the spathe splits longitudinally.


Floral Morphology
The spathe consists of a singular bract that is ribbed, and which remains wrapped around the base of the open flower. Bracteoles are small or absent.
The flowers of Narcissus are hermaphroditic (bisexual). Floral symmetry is actinomorphic (radial) to slightly zygomorphic (bilateral) due to declinate-ascending stamens.
Dissected daffodil flower.
Perianth: Perianth consist of deeply clefted 6 connate segments which may be thought as a ring of 3 sepals and 3 petals (perianth), which are yellow in colour. The perianth is funneliform at the base forming the proximal floral tube or hypanthium. A central bell-shaped crown, or corona, that is frilled at its edges, is the flower’s most conspicuous feature. This 'trumpet' is usually darker yellow in colour. The ring of tepals and the 'trumpet' and  are roughly the same length.
The daffodil’s popularity has resulted in the production of many varieties differing from the yellow parent form mainly in colour; the trumpet and petals may themselves be of contrasting yellow, white, pink, or orange.

Androecium: The trumpet or corona contains six stamens in one to two rows (whorls). Filaments are separate, often of two separate lengths, and attached at the throat or base of the tube (epipetalous). They are straight or declinate-ascending (which curve downwards, then bent up at the tip). The anthers are basifixed (attached at their base).
Illustration of daffodil cross section.
Gynoecium: The ovary is inferior (perianth arises above its apex) and trilocular (three chambered). The pistil is with a minutely three lobed stigma. The filiform (thread like) style, is often exserted (extending beyond the tube).

Fruit
The fruit consists of dehiscent loculicidal capsules (splitting between the locules) that are ellipsoid to subglobose (almost spherical) in shape and are papery to leathery in texture. The fruit contains numerous subglobose seeds which are round and swollen with a hard coat, sometimes with an attached elaiosome. The testa is black and the pericarp dry.

Daffodil capsule with seeds visible inside.
Arbitrary Numbers
The flowers are up to 60 mm long.

Interesting Facts
  • The Latin name was inspired by Narcissus, a figure in Greek mythology said to have fallen in love with his reflection in a pool of water. The nodding head of the daffodil is said to represent Narcissus bending down and gazing at his reflection. 
  • The daffodil is the national flower of Wales, and also the county flower of Gloucestershire.

Useful Links: 
  1. Kew Botanical Garden Record
  2. Glossary of botanical terms
  3. Dessecting a daffodil 

Wednesday, February 10, 2016

Piper nigrum

Piper nigrum (2n=52,78,104...) commonly known as black pepper is cultivated for its fruit, which is used as a spice and seasoning in the dried form. It is also used in traditional medicine.

Piper nigrum spike on the vine.
Scientific classification
Kingdom: Plantae
Subkingdom: Tracheobionta
Superphylum: Spermatophyta
Phylum: Magnoliophyta
Class: Magnoliopsida
Order: Piperales
Family: Piperaceae
Genus: Piper
Species: P. nigrum

Inflorescence
The inflorescence is a pendulous spike or catkin that emerges from the stem node opposite to the leaves. 

Anthesis
Foliage, Flowers and Fruit of the Pepper Plant.
Anthesis occurs in the evening. The flowers open from the base of spike to the tip (acropetal). Pepper is protogynous, i.e., the gynoecium develops before androecium. So generally flowers lower on the spike are pollinated by pollen dehising from those situated above. So the pollination is by geitonogamy (by means of gravity).

Floral Morphology
Wild pepper is dioecious but cultivated varieties are bisexual, and thus more productive. Whitish to yellow-green small sessile flowers are arranged spirally along the spike. Flowers are bracteolate, with four peltate bracts.
Perianth: The flowers are apetalous, infact lack the entire perianth.
Androecium: The androecium is composed of 2-4 stamens on either side of the ovary. The short filaments bear oval shaped anthers with two pollen sacs.
Gynoecium: Gynoecium is composed of a single (or 3-5) carpel(s). At the center of the flower is the  unilocular superior ovary. The style is short with white star shaped stigma. The stigma is covered with a viscous liquid that favour fertilization.

Fruit
Fruits are round, berry-like, up to 6 mm in diameter, green at first but turning red as they ripen, each containing a single seed. The fruit is botanically a drupe and when dried is called peppercorn. 
Green drupes on spike and white (dried ripe) & black (dried unripe) peppercorns

Arbitrary Numbers
The spikes are usually 7-35cm long and bear 70-100 flowers. 50–60 fruits are borne on each spike. Anthesis lasts about 7-8 days.

Useful Links: 
  1. Floral diagram and formula of family Piperaceae
  2. Kew Botanical Garden Record


Tuesday, February 9, 2016

Vanilla planifolia

Vanilla planifolia (2n=32) is a species of vanilla orchid and is one of the primary sources for vanilla flavouring, due to its high vanillin content. 
Vanilla planifolia inflorescence on the vine

Scientific classification
Kingdom: Plantae
Phylum: Angiosperms
Class: Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Vanilloideae
Genus: Vanilla
Species: V. planifolia

Vanilla planifolia 1887 illustration from Köhler's Medicinal Plants
Inflorescence
Inflorescence emerge as a light green protuberance from the leaf axil. It is a 5-8 cm long generally un-branched (rarely branched) raceme

Anthesis
Anthesis is in the early morning. Flowers open acropetaly i.e., from the base of the inflorescence upwards. Each inflorescence has only a single flower open at any one time and a flower lasts only one day.

Floral Morphology
Longitudinal section of Vanilla flower showing Pollinia and Rostellum
Vanilla bears large zygomorphic bisexual flowers that are pale geen or cream or yellow in colour. Flowers are pedicellate, borne on a short pedicel and bracteolate, each flower is subtended by a small pointed bract. flower is turned upside down   (resupinate) as it develops so the labellum is on the bottom.

Perianth: 3 narrow pointed oblong sepals constitute the calyx. Corolla consist of 2 upper petals that resemble the sepals but are slightly smaller, and a trumpet shaped labellum or lip.

Androecium:  A single pollinia is attached to labellum, bearing at its tip 2 pollen masses covered by a cap/hood. 
Dried Vanilla pods with seeds inside

Gynoecium: Concave stigma is  situated below the pollinia is separated from it by a thin flap-like membrane or rostellum, which prevents natural pollination.  Style fused with the filaments of the stamen form the column ogynostemium. Ovary is inferior and long. 

Fruit
Fruit a pendulous, narrowly cylindrical capsule, obscurely 3-angled, splitting longitudinally when ripe. Seeds numerous, globose, non-endospermous, black.

Arbitrary Numbers
On a single wine 7-15 inflorescence emerge in a season. Each inflorescence carries 15-25 large flowers. It takes 50-60 days from floral initiation to anthesis. Flowering period extends 14-30 days. 

Useful Link:Floral formula and floral diagram of Orchidaceae family