The Phenology of sexual reproduction by tropical green seaweeds (Bryopsidales)

This page contains various images and information regarding the appearance of sexual reproductive algae. All photos were taken in the San Blas region of Caribbean Panama. This site is under construction and will be updated with additional images when I have the time. Click here to see microscope shots of seaweed gametes

 

Staged photo showing vegetative and fertile Penicillus spp. side-by-side

 

Note the contrast between a non-fertile thallus on the left and a fertile female on the right (dead thallus from earlier reproduction in the middle)

In this close-up shot of the capitulum of a female P. lamourouxii, you can see the new (uncalcified) growth that gives a all fertile Penicillus their distinctively lighter coloration.
A male Penicillus capitatus releasing gametes

Rhipocephalus phoenix

This "pine-cone" algae assumes a characteristic "bicolored" appearance when fertile, with yellow/cream colored margins above blue/grey or green blades(depending on sex... see next image). Fertility is apparent 48 hours before gamete release, but sexual identity is reliable only during the last 24 hours.

Compare the nonfertile R. phoenix on the left with the fertile female on the right. An Elysia nudibranch is feeding in the crown of the non-fertile specimen

The green, somewhat less corrugated blades noticable to the left are diagnostic of a male. Contrast this color and blade morphology with the female on the right.

 

 

 

 

 

 

 

 

 

 

Udotea spp.

Non-fertile Udotea caribbaea with typical, all green blade and rounded terminal end.

This photograph of a fertile female Udotea cyathiformes recently adorned the cover of the Journal of Phycology. Note pure while stipe and main blade, indicating the migration of all cell contents up into the gametangia. This change from a vegative condition (overall green thallus) occurred overnight

Udotea caribaea fertility
Here's the female.....

This image shows the 3-4 cm long "spikey" gametangia of a female U. caribaea These gametangia grow away from the main thallus blade overnight. Gamete release occurs 72 hours later.

In this close-up of macro-gamete release from a female U. Caribaea, you can see individual eggs (green dots) within the mucilaginous discharge
Click here to see what these gametes look like up close!
..... and here's the male

In contrast to the photo above, here we see the "rounded" gametangia of a male U. caribbaea

As with females, gametes are released from the terminal ends of the gametangia. The photo of microgamete release (below) contrasts sharply with the photo of macrogamete release (above)

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Here you can compare a male (left) and non-fertile (right)Udotea flabellum with a female (far right)